Fix CI issues - Githubissues

Fixes to build on FreeBSD in CI:
- Header alloca.h is not available on FreeBSD.
- Only add libevent includes if found.
- Don't build tests in CI job on FreeBSD when using CMake.
- Skip test/examples using glib if pkg-config is not installed.
- Remove unused test label UT/CT.
Run CI workflow "C/C++ CI"
Get redis_version if valkey_version missing in INFO. Fixes issues in CI job "DB compatibility testing"

valkey-io / libvalkey