Broken out of https://github.com/microsoft/playwright/pull/31727 as per
@dgozman's
[request](https://github.com/microsoft/playwright/pull/31727#discussion_r1685793229).
The PR goal is to remove the `suite` argument from the Component
testing's Vite Plugin. `suite` is used to enrich Vite's dependency graph
with information about dependencies between test suites and helper
files. It essentially merges the Vite graph with the
`compilationCache.ts > fileDependencies` graph, and then writes the
result back into `compilationCache.ts > externalDependencies`.
By refactoring this to make the connection on the reading end in
`collectAffectedTestFiles`, we can drop the `suite` parameter.
We didn't yet have a test that depended on the dependency graph being
connected correctly between `fileDependencies` and
`externalDepedencies`, so I've [extended an existing
test](53a539938b)
to capture that.
* FullConfig split into FullConfig and ConfigInWorker
* FullProject split into FullProject and ProjectInWorker
* Tests can only access {Config, Project}InWorker, while reporters can
only access Full{Config,Project}. This will allow in the future to
change the reporter API independently from the tests.
* Added documentation for the 4 classes.
