Add API::Pagination concern

[mjankowski]

Several related changes:

• Add an API::Pagination concern, and put the existing pagination methods from the api base controller into it
• Add an rspec matcher which wraps up the logic of comparing expected url values to the prev/next header link values, and replace previous specs with this approach -- in some cases this served to remove what was basically a double request call when the checks were in different examples
• Basically every API conrtoller that supports pagination had the same exact method definition of the insert_pagination_headers before_action. Move this to the newly created concern.

I think there is room for more future improvement in this area, but didn't want to go much further than this in first pass.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.05%. Comparing base (86500e3) to head (4b039ef).
Report is 256 commits behind head on main.

❗ Current head 4b039ef differs from pull request most recent head 2a34c30. Consider uploading reports for the commit 2a34c30 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #28826      +/-   ##
==========================================
+ Coverage   85.01%   85.05%   +0.04%     
==========================================
  Files        1059     1039      -20     
  Lines       28277    28092     -185     
  Branches     4538     4532       -6     
==========================================
- Hits        24040    23894     -146     
+ Misses       3074     3038      -36     
+ Partials     1163     1160       -3     

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[mjankowski]

The two linked PRs here show some possible future additions to this concern.

[github-actions]

This pull request has merge conflicts that must be resolved before it can be merged.

[mjankowski]

Rebased this after the max/since one merged. This is probably ready to go as well, but let me know if this would be easier to review in smaller chunks. I could probably pull out the new matcher and spec changes into separate PR, and possibly do the concern changes in 2-3 PRs as well.

Separately, the linked pagination params PR - #28845 - should either be merged first and then incorporated into this change; or if this is merged first, it should be updated to move things to the concern instead of the base class.

[github-actions]

This pull request has resolved merge conflicts and is ready for review.

[github-actions]

This pull request has merge conflicts that must be resolved before it can be merged.

[github-actions]

This pull request has resolved merge conflicts and is ready for review.

[github-actions]

This pull request has merge conflicts that must be resolved before it can be merged.

[mjankowski]

Rebased after #29606 merged - this is now even smaller/cleaner, just moving the pagination-related methods already moved to base class, out to concern.

It would probably be best to review #28845 first, and then rebase this after that one.

[github-actions]

This pull request has resolved merge conflicts and is ready for review.