…mation (#15890)

As part of #15722, the decision was made to change the package.json files for
experimental packages to add 'alpha' identifiers. This ends up causing issues
for our ubergen-ed packages (i.e., aws-cdk-lib), which then try to include L1s
for these packages under the 'alpha' namespaces. Instead, switch (back) to
adding the alpha identifiers as part of the package transformation step.

Reverted the change to the pkglint rules, and re-ran `yarn pkglint` to update
the package.json files.

I also did some light refactoring, since the method was a bit hard to read.

fixes #15845

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The `@aws-cdk/assertions` library was previously excluded from the V2 build of the experimental modules,
because the `vendor.sh` script it used for vendoring in a few modules
(`cfnspec`, `cloudformation-diff`, and `assert-internal`)
used paths relative to the V1 module inside the repository.

Change the `vendor.sh` script to short-circuit and exit when running in `transform` phase for
the alpha packages. That's required because the transform phase re-writes imports when copying
the TS files (because it needs to know which modules are also experimental to do the rewriting correctly),
but the `vendor.sh` script runs only after the `build` script for the package has been invoked,
which means any TS files copied by it successfully would _not_ have their imports re-written.
Since the build for alpha packages runs after the build for `@aws-cdk/assertions`
(we add an explicit dependency to make sure that happens),
those files are already "vendored in" correctly, and will be copied when creating the separate package.

Also adjust the module copying logic to account for bundled dependencies,
which `@aws-cdk/assertion` uses.

Closes #15589

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The proposal for what conventions to use for naming the individually-published
experimental packages has changed a few times, and the current implementation
was the work-in-progress naming.

This change aligns the implementation to the latest proposal.

closes #15576

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…#16112)

One of the steps of the build of experimental packages is to run `yarn --silent jsii-rosetta extract` for each package. Since yarn can't find the `jsii-rosetta` executable, the build fails. For some reason, running `yarn bin jsii-rosetta` at the `individual-packages` folder shows that yarn can find it at the root folder's `node_modules`, but running the same command inside each individual package result in "error Couldn't find a binary named "jsii-rosetta"".

This change adds a `.bin` symlink to each individual package's `node_module` pointing to the root folder's `node_modules/.bin` folder.

Fixes #15825

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#16132)

Both parameters to `find` (the folder to where the search is restricted and what patterns to exclude) should be given by the function parameter, to make sure that they refer to the same folder. Otherwise, we can get errors like `ln: <folder name>: Operation not permitted`.

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I'm not sure whether this is the best place to document these things. I'm happy to move it somewhere else, if someone has a better idea.

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