Add meson option to not install the library

[burlog]

Description

This pull request introduces a Meson build option to allow users to disable the installation of the Catch2 library when using it as a subproject wrap.

The added install Meson option lets users include Catch2 as a subproject with default_options: ['install=false'], effectively preventing it from being installed alongside the main project or library. For example:

catch2_with_main = subproject('catch2-with-main', default_options: ['install=false'])

Catch2's primary purpose is for testing, and when included as a wrap, its installation is often unnecessary. In scenarios where Catch2 is used as a testing dependency, users typically don't want it to be installed with their project.

Currently, the Meson build system doesn't natively support disabling the installation of wraps. While Meson offers a --skip-subprojects flag during installation, it must be manually specified every time meson install is run, which can be cumbersome and error-prone.

This change streamlines the process, improving user experience by eliminating the need for repetitive manual configuration. It aligns with the expected use cases for Catch2 when employed as a testing utility.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.99%. Comparing base (0321d2f) to head (4cd7c0e).
Report is 4 commits behind head on devel.

Additional details and impacted files

@@           Coverage Diff           @@
##            devel    #2940   +/-   ##
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  Coverage   90.99%   90.99%           
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  Files         198      198           
  Lines        8597     8597           
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  Hits         7822     7822           
  Misses        775      775           

[horenmar]

Makes sense, thanks.