snap: add CMake generated snapcraft.yaml and `make snap`
When using "make snap", snapcraft will be used to generate the snap package, if SNAP_BUILD_ONLY option is set, no other configuration is done.
Added also make snap-push- to release
When using "make snap", snapcraft will be used to generate the snap package, if SNAP_BUILD_ONLY option is set, no other configuration is done.
Added also make snap-push- to release