feat: allow specified org domain on sign up

[BruceMacD]

Summary

When a new organization signs up or is created by a support admin it should be possible to specify the org's subdomain or domain directly.

• Allow specifying your organization's sub-domain on sign-up.
• Allow support admins to directly specify an organization's full domain through the API. This may be useful as an admin workaround if we need a special domain. This is not a normal action.
• Update the UI for specified organization domains.
• Parse root errors from conflict error message trace for better error display.

Checklist

• Wrote appropriate unit tests
• Considered security implications of the change
• Updated associated docs where necessary
• Updated associated configuration where necessary
• Change is backwards compatible if it needs to be (user can upgrade without manual steps?)
• Nothing sensitive logged
• Considered data migrations for smooth upgrades

Related Issues

Resolves #2956

[BruceMacD]

I'll update this when #2957 gets in

[BruceMacD]

This prevents the error in the UI from displaying the full trace.

Ex:
An error message of sign-up: create org: duplicate domain becomes duplicate domain