The new descriptions called Catch3 "Catch2's test API with a parallel
runner", which reads as if it were Catch2. Catch3 is a C++ test framework
whose test-writing API is compatible with Catch2's. CMake, Doxygen and both
pkg-config files now say so; the with-main file no longer carries Catch2's
own tagline.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Catch3 is maintained by Progmasoft, but the repository still carried
Catch2's funding links, its maintainer list and GPG keys, a Code of Conduct
contact at a Catch2 maintainer's address, its lists of users, its release
process and release scripts, its AppVeyor configuration and its logos.

- Removed FUNDING.yml, MAINTAINERS.md, appveyor.yml with the AppVeyor and
  OpenCppCoverage helpers, Catch2's user lists, why-catch, release process
  and deprecations pages, its two logos and the major/minor/patch release
  scripts. releaseCommon.py keeps only what the amalgamation reads.
- The Code of Conduct sends reports to support@progmasoft.com.
- contributing.md and release-notes.md are written for Catch3; Catch2's
  release history is linked upstream.
- CMake, pkg-config and Doxygen name Catch3 and its repository; the
  amalgamated files say which Catch3 version and which Catch2 engine they
  come from.

Signed-off-by: Sergio Arroutbi <sarroutb@redhat.com>