workflow: Move release to centralized action
workflow: Move release to centralized action

Creating a GitHub release is complex enough to factorize this into a
central location: https://github.com/cockpit-project/action-release
This is not even specific to cockpit projects.

cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit