fix(wallet)!: Simplify SignOptions and improve finalization logic

[ValuedMammal]

Rather than comingle various SignOptions with the finalization step, we simply clear all fields when finalizing as per the PSBT spec in BIPs 174 and 371 which is more in line with user expectations.

Notes to the reviewers

I chose to re-implement some parts of finalize_input since it's fairly straightforward, see also #1461 (comment). I had to refactor some wallet tests but didn't go out of my way to add additional tests.

closes #1461

Changelog notice

• Removed field remove_partial_sigs from SignOptions
• Removed field remove_taproot_extras from SignOptions

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

Bugfixes:

• This pull request breaks the existing API
• I've added tests to reproduce the issue which are now passing
• I'm linking the issue being fixed by this PR

[storopoli]

Concept ACK.

Nice trick with mem::take.

[evanlinjin]

ACK ee8d410

Just a small nit lol

[evanlinjin]

re-ACK 996605f