add set-host command

[nicbus]

This PR adds the set-host command to set opret/tapret host, if needed.

This is intended to be called by a user that has prepared a PSBT with an output ready for the commitment but needing to set it as a host, via CLI.

This comes from (and depends on) rgb-wallet PR #46, which initially did the same in the pay command but now only makes opret and tapret modules public.

[dr-orlovsky]

Some style improvements - otherwise LGTM. Why draft?

[nicbus]

Some style improvements - otherwise LGTM

great, updated

Why draft?

This PR was set as draft since it could not work until rgb-wallet PR 46 was not merged.

note: I now introduced a commit that updates rgb-wallet and rgb-std to git/master so the set-host command can use the now-public opret/tapret modules.

[nicbus]

added a commit to update an outdated github action (actually to re-trigger CI as it failed for an internal error on the previous run)

it still failed, though, with more internal errors

the PR IMO is ready, the only test that failed in the previous run (build/cli) succeeds locally (cargo build --no-default-features --features cli)

[dr-orlovsky]

ACK with nits. If you want, I can merge it as is; but if you prefer to address nits, this is also an option

[nicbus]

ACK with nits. If you want, I can merge it as is; but if you prefer to address nits, this is also an option

liked the suggestions, updated

[dr-orlovsky]

ACK 2237967

Very cool, thank you!