feat: Add support for Multipath (two-path) descriptors

[tvpeter]

Description

This PR enables support for BIP389 multipath descriptors. It uses the existing external descriptor and verifies whether the provided descriptor is a multipath descriptor. If it is, a wallet will be created using the Wallet::create_from_two_path_descriptor() method. If not, the standard wallet creation logic will be applied.

Fixes#195

Replaces #238

Notes to the reviewers

• is_multipath_descriptor helper parses the descriptor and accepts only two-path multipath descriptors (external/internal).

Changelog notice

• Add support for BIP389 multipath descriptors

Checklists

All Submissions:

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

New Features:

• I've added tests for the new feature
• I've added docs for the new feature
• I've updated CHANGELOG.md

[codecov]

Codecov Report

❌ Patch coverage is 83.63636% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.80%. Comparing base (e7223e5) to head (48b3314).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/persister.rs	68.96%	9 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## master #309 +/- ##
==========================================
+ Coverage 57.45% 57.80% +0.34% 
==========================================
Files 22 22 Lines 3695 3728 +33 ==========================================
+ Hits 2123 2155 +32 - Misses 1572 1573 +1 

Flag	Coverage Δ
rust	57.80% <83.63%> (+0.34%)	⬆️

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[sdmg15]

tACK 48b3314