fix(rust/signed-doc): Fixing collaborators metadata field and DocumentOwnershipRule validation rule

[Mr-Leshiy]

Description

Fixed decoding of the collaborators metadata field and DocumentOwnershipRule validation rule with among with some cleanups and providing more tests

Description of Changes

• Modified DocumentOwnershipRule validation logic
• Refactored and added more tests cases for DocumentOwnershipRule
• Fixed collaborators decoding, it should be always in URI form and contains at leas one CatalystId entry
• Updated collaborators cddl specs.

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 | ${\color{lightgreen}Pass: 530/530}$ | ${\color{red}Fail: 0/530}$ |

[apskhem]

LGTM