feat(catalyst-python): Modify signed_doc module interfaces.

[Mr-Leshiy]

Description

Needed for input-output-hk/catalyst-voices#3817.

Related Issue(s)

Part of input-output-hk/catalyst-voices#3788

Description of Changes

• Added new DocumentRef type.
• Modified all document generators functions, with adding optional arguments id and ver, replace SignedDocumentBase arg types with new DocumentRef.

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]

📚 Docs Preview

The docs for this PR can be previewed at the following URL:

https://docs.dev.projectcatalyst.io/libs/feat/signed-doc-create_metadata

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 601/601}$ | ${\color{red}Fail: 0/601}$ |

[apskhem]

LGTM