Implement `scid-alias`

[t-bast]

Once dual-funding support has been shipped, we should implement scid-alias support.
We're currently using a hacky alias that potentially has collisions.

[pony-montana]

hi, its this still pending? Also, is the aliased scid used in the actual implementation private? Or is it leaking the funding tx of the channel when shared in phoenix bolt11 invoices?

[pony-montana]

@t-bast Hi, I also opened an issue here ACINQ/phoenix#631
I didnt find really anything about scid alias in documentation, faq, precedent issues, nothing.
Thanks for clarification, I think is an important piece of the privacy of lightning anannounced channels and should be advertised if its used (at least until we will live in bolt12 standard).

[pm47]

its this still pending?

Yes

is the aliased scid used in the actual implementation private?

Yes

is it leaking the funding tx of the channel when shared in phoenix bolt11 invoices

No