[Release/CI] Adjust release pipelines to support new tags and delete rococo from release (#6108)

This PR introduces adjustments to the release pipelines so that it could
be used with the new tags in the form of `poilakdot-stableYYMM(-rcX)` in
addition to the old form of tags like `vX.XX.X`.

Also, the rococo runtime and its parachains are deleted now from the
build and release draft as it is decommissioned and not used any more