Add SonarQube Generic Test Data reporter

It outputs reports in the `Generic Execution Test Data` format, see
https://docs.sonarqube.org/latest/analysis/generic-test/, specifically
https://docs.sonarqube.org/latest/analysis/generic-test/#header-2

Close #1738 (this is a cherry-pick and fixup of that PR)

docs/release-process.md

@@ -42,8 +42,8 @@ Tag version and release title should be same as the new version,
 description should contain the release notes for the current release.
 Single header version of `catch.hpp` *needs* to be attached as a binary,
 as that is where the official download link links to. Preferably
-it should use linux line endings. All non-bundled reporters (Automake,
-TAP, TeamCity) should also be attached as binaries, as they might be
+it should use linux line endings. All non-bundled reporters (Automake, TAP,
+TeamCity, SonarQube) should also be attached as binaries, as they might be
 dependent on a specific version of the single-include header.
 
 Since 2.5.0, the release tag and the "binaries" (headers) should be PGP