Add Ability to Remove Recent Workspace

Fix issue #1051 by providing a contextual menu
when right clicking a recent workspace.
Refactor Recent Menu Behavior

Update behaviors used to implement right click menu for a recent workspace to
reuse existing behaviors. Refactor the sidebar-menu behavior to utilize the
same on-menu behavior.
Remove extraneous behavior
Ensure destruction of recent workspaces
Merge pull request #1138 from mortalapeman/master

Add Ability to Remove Recent Workspace