4.20.7

- tasklist: Destroy group menu item if window is closed
- panel: Make non-GObject internal plugins resident
- Revert "plugins: Do not use g_intern_static_string"
- panel: Do not fall through when internal plugin failed to load
- wayland: panel: Track set_anchor_default source id
- plugins: Do not use g_intern_static_string
- panel: Fix wrong memory management
- panel: Be sure to set plugin properties when appropriate
- Set application name so internal plugins can't override it
- plugins: Reset workspace group when needed
- wayland: Guard layer-shell related code also at runtime
- wayland: Review screen layout change management
- common: Only remap widget if visible
- wayland: autohide: Fix autohide of floating panel
- wayland: Handle null workspace group list when a group is destroyed
- wayland: panel: Delay hiding panel window when screen layout changes