As agreed in the PTG[1], remove the monasca datasource that was deprecated in the 2025.2[2] since it the project was marked as retired. This change removes the monasca datasource, all its configuration options and its unit tests. [1] https://etherpad.opendev.org/p/watcher-2026.1-ptg#L200 [2] https://review.opendev.org/c/openstack/watcher/+/956968 Assisted-By: claude-code (clade-sonnet-4.5) Change-Id: I5ba49e84af61165af8b3c38e21ae0c0a47bd70d8 Signed-off-by: jgilaber <jgilaber@redhat.com>