[feature] Allow migration / move to be reversible

[stillnotstars]

Is your feature request related to a problem ?

hi! reporting on behalf of another user on my instance who moved accounts away from GTS expecting the action to be reversible, similarly to mastodon, which allows you to cancel a redirect to make your account functional again. the actual text on the account migration page does not actually specify what the serious and irreversible consequences of the action are, only listing them in the documentation which requires opening another tab.

1. mastodon's UI for moving accounts lists out what account migration will do-- can there be a similar warning in the GTS UI?
2. are there plans to make it possible to reactivate a migrated account?

Describe the solution you'd like.

it would be nice to be able to reactivate a migrated account, or else more obviously specify that migration will make an account permanently read-only.

Describe alternatives you've considered.

none

Additional context.

No response

[tsmethurst]

We'll do this in 0.19.0 probably, as it seems there's more demand for it than we first anticipated!