Permissions Grants for `MessagesGet`

[LiranCohen]

This PR modifies MessagesGet to better suit it's use and support permissions.

• MessagesGet now only supports getting a single message
  • If a message has data, it will be provided via a data method similarly to ReocrdsRead
• Can Grant Permissions for MessagesGet scoped
  • Allows unrestricted scope (no protocol scope spcified)
  • If scoped to a protocol and the message to get is a Permissions-Protocol record, it will match against the scope.
  • Delete messages are matched against the protocol of the RecordsWrite they reference

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 98.69%. Comparing base (d96caec) to head (b82212b).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #748 +/- ## ========================================== + Coverage 98.66% 98.69% +0.02% ========================================== Files 73 74 +1 Lines 11091 11268 +177 Branches 1584 1609 +25 ========================================== + Hits 10943 11121 +178 + Misses 142 141 -1 Partials 6 6 ```

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