run-make-check.sh: Adding ccache tuning for the CI

run-make-check.sh: Adding ccache tuning for the CI

When run-make-check is run by the CI, some tuning can be performed to
speedup the build.

This commit :
- Detect jenkins by searching JENKINS_HOME env variable
- Defines the SOURCE_DATE_EPOCH to enforce a stable date across builds
- Ask cmake not to use the git versioning which adds useless entropy for a temporary build (ENABLE_GIT_VERSION=OFF)
- Define the ccache slopiness to increase efficiency
- Increase the ccache size to save multiple builds to maximise cache hit between PRs
- Print ccache statistics to evaluate ccache efficiency

Signed-off-by: Erwan Velu <erwan@redhat.com>