allow managing users from admin panel

[mastercactapus]

Is your feature request related to a problem? Please describe:
It is not currently possible to do anything other than adding users via the CLI for basic auth.

Describe the solution you'd like:
Perform the following from within the GoAlert web UI:

• Add users (@dctalbot)
• Delete users (@dctalbot and @KatieMSB)
• Change user roles (@arurao)
• Allow users to change their password when Basic auth is enabled from Profile
• Consolidate UI into centralized dashboard - may be out of scope/needs more discussion on design

Describe alternatives you've considered:
These steps are only currently possible with direct DB access and knowledge of GoAlert internals.

[Forfold]

• Allow users to change their password when Basic auth is enabled from Profile

This would be a good candidate for #1068

[stale]

This issue has been automatically marked as stale because it has not had recent activity.