Enabled ninja build for CTA
Summary
Adds support for Ninja as a build generator. Make is still able to be used. Which build generator to use can be specified by a flag in the build_rpm
script. Note that this is only enabled for the rpms for now; not the srpms as these only rarely need to be rebuilt.
Requires manual tests in pre-production
NO
References
Depends on the build script and containerized compilation introduced in #725 (closed) and #724 (closed) respectively.
Closes #355 (closed) Closes #781 (closed)
Edited by Niels Alexander Buegel