* Depends on #3001
* Part of #2919
* Fixes #2917
* Solves a big chunk of #2873

### What

Introduces a very simple `rerun::Result`. I decided to keep it **a lot**
more simple than the arrow Result type and refrained from the typical
"return or assign" etc. macro since I noticed that they get quite
complicated quickly.

The idea is that the rerun result type won't be needed by a lot of
manual code, so erring on the too lightweight side should be in our
favor.

We use this now accross the entire public serialization path - meaning
that once we move out array->arrow serialization helper into separate
headers we should be pretty much done with not exposing arrow headers!


### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/3005) (if
applicable)

- [PR Build Summary](https://build.rerun.io/pr/3005)
- [Docs
preview](https://rerun.io/preview/pr%3Aandreas%2Fcpp%2Fcustom-result-type/docs)
- [Examples
preview](https://rerun.io/preview/pr%3Aandreas%2Fcpp%2Fcustom-result-type/examples)

* Part of #2919
* Depends on #3001
* Solves C++ part of #2537

### What

Moves out all affix-fuzzer and co. testing types of the actual SDK.

While working on that...
* I figured out why warnings from arrow headers showed up only
sometimes: When Arrow isn't added explicitely as a dependency, CMake
doesn't seem to declare it as system header which normally suppresses
warnings (as you can imagine this got really bad now when adding more
cpps that include arrow to the test library). Obvious workaround is to
add arrow explicitly to the text executable.
* internal include paths got shorter/more natural in some cases. I had
to make the `Includes` utility more clever in order to support types
outside of the sdk, so we got this almost for free :)

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/3007) (if
applicable)

- [PR Build Summary](https://build.rerun.io/pr/3007)
- [Docs
preview](https://rerun.io/preview/pr%3Aandreas%2Fcpp%2Fseparate-test-types/docs)
- [Examples
preview](https://rerun.io/preview/pr%3Aandreas%2Fcpp%2Fseparate-test-types/examples)

### What
This is so we can test things out before the next release, and also get
in some new egui features for the plot aggregator and drag-and-drop.

* Closes #4716
* Closes #4794

### TODO
* [x] Fix hovering ListItems in blueprint panel

### wgpu changelog
https://github.com/gfx-rs/wgpu/blob/trunk/CHANGELOG.md#v0190-2024-01-17

### relevant egui changelog (so far)

#### eframe
* Keep `ViewportInfo::maximized` and `minimized` up-to-date on Windows
[#3831](emilk/egui#3831) (thanks
[@rustbasic](https://github.com/rustbasic)!)
* Update wgpu to 0.19 [#3824](emilk/egui#3824)
* Fix: handle `IconData::default()` without crashing
[#3842](emilk/egui#3842)

#### egui_extras
* Fix unwraps in SVG scaling
[#3826](emilk/egui#3826) (thanks
[@amPerl](https://github.com/amPerl)!)
* Update to ehttp 0.4 [#3834](emilk/egui#3834)

#### egui_plot
* Make `egui_plot::PlotMemory` public
[#3871](emilk/egui#3871)

#### egui
* Selectable text in Labels
[#3814](emilk/egui#3814)
* `ComboBox`: add builder method for height
[#3001](emilk/egui#3001) (thanks
[@hinto-janai](https://github.com/hinto-janai)!)
* Add keys `?`, `/`, `|`
[#3820](emilk/egui#3820)
* Fix clickable widgets blocking scrolling on touch screens
[#3815](emilk/egui#3815) (thanks
[@lucasmerlin](https://github.com/lucasmerlin)!)
* Fix `stable_dt` [#3832](emilk/egui#3832)
* Bug Fix : `Response::is_pointer_button_down_on` is now false the frame
the button is released [#3833](emilk/egui#3833)
(thanks [@rustbasic](https://github.com/rustbasic)!)
* Use runtime knowledge of OS for OS-specific text editing
[#3840](emilk/egui#3840)
* Refactor: move text selection logic to own module
[#3843](emilk/egui#3843)
* Fix: dragging to above/below a `TextEdit` or `Label` will select text
to begin/end [#3858](emilk/egui#3858)
* Add `Response::contains_pointer`
[#3859](emilk/egui#3859)
* Always set `response.hovered` to false when dragging another widget
[#3860](emilk/egui#3860)
* Add `Align2::anchor_size`
[#3863](emilk/egui#3863)
* Add `Context::debug_text`
[#3864](emilk/egui#3864)

#### epaint
* Add `Align2::anchor_size`
[#3863](emilk/egui#3863)

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[app.rerun.io](https://app.rerun.io/pr/4885/index.html)
* Using examples from latest `main` build:
[app.rerun.io](https://app.rerun.io/pr/4885/index.html?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[app.rerun.io](https://app.rerun.io/pr/4885/index.html?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/4885)
- [Docs
preview](https://rerun.io/preview/eb1bce846c3adb29b99d04018b002475994ad213/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/eb1bce846c3adb29b99d04018b002475994ad213/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

---------

Co-authored-by: Andreas Reich <r_andreas2@web.de>