Added request channel form.

This pull request fixes issue #10.

Goals:
- [x] Add a link to the homepage to request channel.
- [x] Don't allow duplicate channel to be requested
- [x] Email admins after request
- [x] Create in-active channel, to be used by admin.
- [x] Breakout landing page base template
- [x] Make sure it doesn't trigger a channel refresh.
- [x] Validate server name, should be formatted as `<domain>:<port>`