Add GetBlockTemplate RPC functionality

[Gudnessuche]

During a conversation with Luke Dash Jr, Jason Hughes and Bitcoin Mechanic from Ocean Mining during a stream had, on how to use DATUM, my question to them on configuring DATUM with Floresta seemed to have fallen on deaf ears at first, cos they hadn't heard of floresta. However, they made a follow up admission that even if they were to consider, Floresta didn't allow for GetBlockTemplate RPC.

I believe this would be a massive addition to enable a future where Ocean's adoption could be tethered to Floresta's adoption

[Davidson-Souza]

This is something that we have down in our roadmap. Right now we need to get things moving on mempool, I'm working on the utreexo side of things (just merged a major milestone towards that).

I had some other people showing interest in having gbt support, if this is actually something that people would like, I certainly can prioritize it (I've been running this as a low-prio for now)

[Gudnessuche]

Please prioritize this, for the Ocean team to gob smacked when asked about Floresta. I want to be able to let em know, when next they're on stream, that Floresta fixed the GBT RPC. Maybe in the future we can talk about BOLT 12 integration

[jaoleal]

If @Davidson-Souza agrees, this single feature doesn't seem to be difficult to implement and would be a good start for 0.8.0 I think... I notice the lack of some other RPCs and this could be the start of implementing the missing ones.

[Gudnessuche]

Thought @Davidson-Souza ?

I believe this RPC would be a game changer for DATUM user

[Davidson-Souza]

Thought @Davidson-Souza ?

I believe this RPC would be a game changer for DATUM user

Sure, we can prioritize this for the next release. Added to v0.8 milestone

[Gudnessuche]

Nice