feat: increase isolated app balance

[rolznz]

Closes #479

Adds ability to "Increase" the balance of an isolated app in 3 places (new isolated app connection, isolated app connection page, friends & family app)

Also renames the db service as this only had app-related functionality, and cleaned up some previous TODOs there.

I am not sure about the naming, because this is a custodial thing and you can actually just print paper money using it. It's not a real topup, so on the UI it's just called "Increase".

[bumi]

Is it possible to set this also similar to the budget also when creating the connection?

print paper money using it

I don't think your comparison his correct here. there is no "paper money'. It allows a connection to spend a certain amount. and maybe the admin allows a connection to spend the same money that the admin already promised to another connection.

But we're not building a bank or a financial system here, so I think you should not try to compare it to that.
It's an app to manage sats and that allows the owner of the sats to give some people the permission to spend those sats.
comparing a wife-husband relationship to a broken financial system or to some bank is imo flawed. We need to think what the user wants and what makes sense for that setup.

[rolznz]

@bumi

Is it possible to set this also similar to the budget also when creating the connection?

I think we can. Internally it'd still need to create and pay an invoice after the app is created, but the UX flow might be better that way, true.