Pass RestClientCache as constructor param

[dmjb]

Relates to #2845

This has been broken out of a larger PR for ease of review.

The RestCacheClient is used in several parts of the code, but is always passed as an option. In some places (which will be changed in a subsequent PR) this is used as a form of dependency injection. However, this pattern has caused problems in some of the refactoring I am doing.

This PR changes the code so that it is passed around explicitly to the constructor methods of the structs/interfaces which need it. This is an interim step - the desired end state is that the RestClientCache is hidden from most of its current clients, and only the GitHub ProviderClassManager will depend on it (along with the Github trait instances it produces). ProviderBuilder has not been changed - that is because I am working towards getting rid of that struct.

This PR also introduces a no-op implementation of the RestClientCache interface. Previously, code had to explicitly check that it was not nil before using it. In future PRs, I will get rid of some of these guards.

Summary

Provide a brief overview of the changes and the issue being addressed.
Explain the rationale and any background necessary for understanding the changes.
List dependencies required by this change, if any.

Fixes #(related issue)

Change Type

Mark the type of change your PR introduces:

• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

Outline how the changes were tested, including steps to reproduce and any relevant configurations.
Attach screenshots if helpful.

Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 50.63% (+0.01%) from 50.617%
when pulling fc2fccf on rest-cache-cleanup
into 2d28734 on main.