Allow creating a recurrence from a transaction

[simhnna]

You should be able to easily create a recurrence from a transaction. It would prefill everything except the recurrence field.

This would also be the way to create a recurrence when it would involve an account that has not been created yet.

[roanutil]

Are you open to the idea of making recurring transactions a subset of transactions? Instead of having a dedicated place in the UI with a separate create and update flow, it may be better for all transactions to have a recurring interval as an option. This loops in issue #5 as well.

[simhnna]

yeah, I even tried writing some code for that myself but wasn't happy with it...
AFAIK I ended up with three different types of transactions:

1. past transactions
2. future transactions
3. next recurrence

But it was a mess, which is why I erased every bit of that code :D

If you have ideas on how to model this in a clean way I'm all for it!