feat(rust/signed-doc): DocLocator validation during fetching from the CatalystSignedDocumentProvider

[Mr-Leshiy]

Description

Implemented a proper DocumentRef validation with the referenced document which was fetched from the provider.
The DocumentRef value from the metadata field must exactly match with the actual DocumentRef calculated from the fetched document.
This way we are ensuring that the provider would return a correct document, according to the asked DocumentRef.

Refactored ChainRule::check method, use doc_refs_check to apply full set of DocumentRef checks.

Related Issue(s)

Closes #644

Description of Changes

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

[stanislav-tkach]

LGTM, but Clippy isn't happy with the check function size. I propose to make the validator lambda a separate function instead of adding the allow attribute.

[github-actions]

📚 Docs Preview

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

https://docs.dev.projectcatalyst.io/libs/feat/full-doc-ref-check

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 566/566}$ | ${\color{red}Fail: 0/566}$ |

[apskhem]

LGTM