feat(rust/signed-doc): New implementation of DocType

[bkioshn]

Description

New implementation of DocType

Commit pick from #338

Changes

Additional modifications were introduced beyond what was originally approved.

• rust/signed_doc/src/validator/mod.rs -> Rule should be backward compatible. Confirm with frontend that single UUIDv4 is now changing to list of UUIDv4 eg. 7808d2ba-d511-40af-84e8-c0d1625fdfdc to [7808d2ba-d511-40af-84e8-c0d1625fdfdc]
• Rename + Restructure doc_types/mod because the old one is confusing

Related Issue(s)

• Frontend - feat(cat-voices): DocumentType list value catalyst-voices#2571
• Catgateway - fix(cat-gateway): Modify doc type catalyst-voices#2716
• Original PR Catalyst Signed Documents type field #328

Breaking Changes

Must not be any breaking change, should be compatible with the old implementation

Please confirm the following checks

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream module

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 336/336}$ | ${\color{red}Fail: 0/336}$ |

[stevenj]

This looks fine.
But do not merge to main until its tested with the FE.
Also confirm with QA before merging this and the matching FE to see if its OK to land before the next dry run. Which is my preference.