[DIFE-1970] Remove hide events function in admin dashboard

DIFE-1970

Change log

• Added:
• Changed:
• Deprecated:
• Removed: The Hide meeting functionality, containing:
  • Hide / Unhide meeting command
  • Hide / Unhide routes entry
  • Deface override that adds Hide / Unhide functionality
  • Various meeting overrides in regard of Hide / Unhide functionality
  • Related locales
• Fixed:
• Security: