Catalyst Signed Documents `ver` field validation specification

[Mr-Leshiy]

Summary

Current ver validation description is not full and does not covers all the necessary validation scenarios.
Missing rules:

• New document ver should be greater that the latest known submitted.
• New document type should be the same that the latest known submitted.

Cleanup:

• Moving the id validation description to the ver field as its more related to the proper document versioning, rather than identifying the id field.

- IF `ver` does not == `id` then a document with \n`id` and `ver` being equal *MUST* exist.

Related PR

These changes already done on the library side
#497