feat: introduce crate::sync module and its APIs

I decided to open a separate MR as a continuation of work done in !543 (closed) as I updated the commit history to be more fine-grained and be relevant even without squash.

The important updates are in fix: use vclock instead of lsn commit:

1. Uses the @rosik suggestion to use explicit request and response types instead of macro
2. It continues with crate::sync structure that we decided on in pair programming session
3. In some limited cases (when there are no arguments) it uses call_raw method.
4. Refactors a bit check_vclock_and_sleep - Vclock interface makes this function easier to write
5. Adds rust unit tests for some stored procs

Closes #274 (closed) Closes #175 (closed)