add Catch2 unit test library wrapper

[igrr]

Change description

This PR adds Catch2 unit testing library.

In addition to a simple CMake wrapper around the library, the component provides a register_catch2 function to register an ESP-IDF console command to invoke Catch2.

Two examples are provided:

• a basic example which works both on host and target
• a console example

Minimal supported version is set to v5.0, since earlier IDF releases didn't have WHOLE_ARCHIVE component property, which made linking all the tests tricky.

Checklist

• [x] Component contains License
• [x] Component contains README.md
• [x] Component contains idf_component.yml file with url field defined
• [x] Component was added to upload job
• [x] Component was added to build job
• [x] Component contains examples
• [x] CI passing

[github-actions[bot]]

Unit Test Results

  11 files  ±0    11 suites  ±0   15m 18s :stopwatch: +5s   27 tests ±0    27 :heavy_check_mark: ±0  0 :zzz: ±0  0 :x: ±0  252 runs  ±0  252 :heavy_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit da1c0f70. ± Comparison against base commit 07871a42.

:recycle: This comment has been updated with latest results.