Simplify build procedure to improve portability and not to depend on platform specific tools like yum and rpm

Problem to solve

Make CTA and the CTA build procedure portable to other Linux distributions. Don't depend on yum and rpm for the build process. Allow for development and debugging of several versions in parallel on the same machine, by being able to launch the applications from the build tree without install step. Only the install step should require sudo and is only needed for final deployment.

This will make the system more accessible to third-party developers making collaboration easier.

Stakeholders

All developers and hence the CTA user community.

Proposal

Review the current build procedure and change it such that all dependent packages, currently pulled in via RPM repos, are pulled in directly by cmake, either in source form or in platform dependent binary form (to reduce compile times). This way the build tree will contain all that is needed to run and test the CTA programs. Only for final deployment "sudo make install" will be needed. The system wide tools like compilers, git, cmake, ninja, etc will be installed only once via a prerequisites.sh script.