Add Gateway Mnemonic support to UI

[Kodylow]

need to add support for new gateway mnemonic coming in fedimint 0.5, @m1sterc001guy is this just adding that "/mnemonic" authed route to fetch and display it? Is there a setup state we can put the gateway into where it doesn't have it set yet then the user passes it in? kinda like we do pre setup ceremony for the guardians?

[m1sterc001guy]

is this just adding that "/mnemonic" authed route to fetch and display it?

Yes

Is there a setup state we can put the gateway into where it doesn't have it set yet then the user passes it in? kinda like we do pre setup ceremony for the guardians?

Not currently. If it is not set, a new mnemonic is generated. The user can pass it into the gateway via an environment variable. If you want an explicit setup state, we can add that, but would require a little re-working.

Do you also want to add a "migrate" function to that UI to migrate old connected federations to the new mnemonic way? We don't currently have that feature either but we could add it if it would be helpful.

[Kodylow]

I think for people setting gateways up using a service it'd be good to not have them input the mnemonic anywhere else besides our UI

[Kodylow]

and on migrating I don't want that in the UI, lets keep that server side / manual