Admins can see all invites

[cecyc]

Added view in admin dashboard for admins to see all meeting invites.

To do this, I had to:

• Move invite create method (formerly Meetings Controller > Invite) to Invitations Controller
• Added ability to delete invites to controller
• Created invitations folder in views
• Added show.html.erb to invitations views
• Added form to create new invitations to show page

[alejandroereyes]

:+1:

[wrpaape]

:+1:

[Graciexia]

Admin does not need to create invitations which are sent by the meeting creator, so could you pls move the "invite method" back, otherwise it will crush the invitations os meeting show page.