This centralizes the code for resource handling into the `resource.py`
file under a new `Resource` class. Notably, `DefaultResources` has been
removed, its functionality rolled into the new class. The same class is
now used for handling global resource limits, default resources, and
rule resource constraints

As a result of this standarization, the following bugs/inconsistencies
are fixed:

1) humanreadable resources can now be specified in a group job in
cluster submit without crashing the program (#3367)
2) `mem`, `mem_mb`, and `mem_mib` can now be used interchangeably across
`--resources`, `--set-resource-scopes`, `--default-resources`,
`--set-resources`, and the `resource` keyword within a `Snakefile`, as
the names are internally standardized.
4) humanreadable resources can now be used in all resource contexts
(e.g. `--resources`)
6) Providing the same effective resource twice (e.g. mem, mem_mb and/or
mem_mib) in the same rule or in the global resource specification raises
an error.
7) **BREAKING** `mem_mb` and `mem_mib` can no longer be provided a
string or a function that returns a string within a rule.
8) The `{resources}` object available within a shell command or
parameter context now has access to all versions of a sized resource,
e.g. `mem`, `mem_mb`, `mem_mib`. `mem` is now always a string with a
unit.


A few additional changes:

- The old `Resource` class in snakemake/io.py (that subclasses
`Namedlist` was renamed to `ResourceList` to prevent confusion. This
class is still used within the `Job` class and is ultimately passed onto
the executor. This ensures compatibility with the existing plugin
interface.
- I added the ability to watch for a specific Exception class within the
tests to help increase the resolution of some of my "failure" tests.
This is completely backwards-compatible
- Additional typing annotations were added throughout the code I
touched.
- A small rearrangement in the code within snakemake/workflow.py to
group the resource-related code together.

### Outstanding issues (not to be resolved here)
1. It was, and remains, possible to sneak a string value as a thread
using `--set-threads` with a python expression
1. --resources cannot be given an expression, per design. Currently,
though, nothing stops one from from providing an expression directly via
the api. This problem preexists this PR.
3. There is currently no testing of the cli parsing functions. This
should be written in a new PR.
4. The check for positive integers is only done for the CLI. Resources
requested within rules will not be so validated. This is unchanged from
previous

### Gotchas
1. This does represent a breaking change for API use, as the dataclasses
will not perform any automatic conversion. Specifically,
ResourceSettings.resources, .overwrite_threads, .overwrite_resources,
and .default_resources will be broken in dependent apps.



<!--Add a description of your PR here-->

### QC
<!-- Make sure that you can tick the boxes below. -->

* [x] The PR contains a test case for the changes or the changes are
already covered by an existing test case.
* [x] The documentation (`docs/`) is updated to reflect the changes or
this is not necessary (e.g. if the change does neither modify the
language nor the behavior or functionalities of Snakemake).


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

# Release Notes

* **New Features**
* Support for human-readable resource specifications (e.g., "1 GB", "1
GiB")
* New resource units: mem_mib, disk_mib alongside existing mem_mb,
disk_mb

* **Bug Fixes**
  * Improved resource handling and validation with better error messages
  * Enhanced resource constraint detection and reporting

* **Refactor**
  * Unified resource management system for simplified configuration
  * Streamlined CLI resource parsing and argument handling
<!-- end of auto-generated comment: release notes by coderabbit.ai -->