admin: Switchover

[mastercactapus]

What problem would you like to solve? Please describe:
As an on-call system uptime is extremely important, but it is also necessary to switch DB servers for things like patching, new versions, moving geographic regions, etc... without service interruption.

Describe the solution you'd like:
Adding a new page under the Admin panel, to allow a switchover to be performed easily.

• Should be obvious when complete
• Have information when SWO mode is not enabled (and how to enable it)
• Display information about DB versions/connections and current progress

Describe alternatives you've considered:
There is currently an interactive CLI tool to perform this.