feat(rust/signed-doc): Catalyst Signed Documents validation initialisation fully during the runtime

[Mr-Leshiy]

Description

Its a refactoring from get ridding of macro code generation for the instantiation of the validation rules and moved such implementation as a plain Rust functions.

The main reason, that not all of the part is possible to instantiate during the compile time (e.g. JSON schema instance) and the only way how they could be instantiated its only the runtime, so it would become a mix of some things are evaluated during compile time, but some stuff evaluated during runtime still.
Which sounds we are overcomplicating things without no gain

Related Issue(s)

Part of https://github.com/input-output-hk/catalyst-internal-docs/issues/266
Closes #510

Description of Changes

• Added a new catalyst-signed-doc-spec crate, which contain a definition of the signed_doc.json types.
• Implemented ContentEncodingRule initialisation.
• Moved all validation rules initialisation into the catalyst-signed-doc crate from the catalyst-signed-doc-macro
• Cleaned up catalyst-signed-doc-macro crate.

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 | ${\color{lightgreen}Pass: 448/448}$ | ${\color{red}Fail: 0/448}$ |

[saibatizoku]

LGTM