Updated Track Details view to only render Performer Credits and its caption when there are any.
Added "delete agent disabled" check for artists referenced by any albums.
Updated Related Albums on Agent Edit page to reflect all albums the agent is associated with.
Updated Related Albums on Agent level to display the role of that agent.
Updated the Related Albums of an Agent to render distinct albums and a group of roles.
Updated Agent Details page to show Related Albums and its roles per album.
Updated Track Details page to only render information if there is any.
Changed the Artist meta element's contents by only including artists from Album, Track and Track Performer credits, excluding duplicates.
Fixed a bug where related entities were undeletable even though the album referencing them was deleted.
Merge branch 'feature/WR7' into develop