set opret/tapret host if needed

[nicbus]

This PR adds support for automatically setting opret/tapret host if needed.

The implementation is similar to my previous rgb-std PRs #14 and #15.

Note: I made the opret and tapret modules from psbt public (and not just pub(crate)) as they're also useful outside of rgb-wallet (e.g. we need to use opret in rgb-lib).

[dr-orlovsky]

This will wipe the first OP_RETURN if it is present in the tx (doe to some reason) and will force the first tapret to host the commitment, even if it was not intendend. Why we do not leave marking the proper outputs to the wallet devs?

[nicbus]

This will wipe the first OP_RETURN if it is present in the tx (doe to some reason) and will force the first tapret to host the commitment, even if it was not intendend. Why we do not leave marking the proper outputs to the wallet devs?

Doing so from a rust piece of software is not an issue, provided opret/tapret modules are public.
Using the CLI only, on the other hand, I don't see a way to do the same, without adding an ad-hoc tool to prepare the PSBT to host the commitment.

Taking that into consideration, I think the best approach is thus to:

• modify this PR to only make opret/tapret modules public
• open a PR on RGB-WG/rgb to add a command that only sets opret/tapret, so it can be called only if needed

If you agree I'll be glad to proceed this way.

[dr-orlovsky]

Yes, I agree that this is the best approach

[nicbus]

Yes, I agree that this is the best approach

PR updated dropping automatic setting of commitment host and only making the required modules public.

[dr-orlovsky]

ACK 0d395e1