Update release process ADR with info on Rust crate

[NlightNFotis]

Update the release process ADR with information on the
Rust crate publishing, along with some information on its
versioning schema and choices.

• Each commit message has a non-empty body, explaining why the change was made.
• Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[TGWDB]

Outside the scope of this PR, but should this be allowed or prevented? Are there times when this is safe and times when it could yield problematic outcomes?

[NlightNFotis]

The Rust API needs to link against libcprover.x.y.z.a to use the functions exposed by the C++ API.

If the C++ API functions haven't been subjected to an interface change for the existing functions, then this should be safe.

Of course, there cannot be too wide a divergence between versions of the Rust and C++ API it depends on.

In my personal experiments, I have linked the Rust API version 5.80.0 against libcprover.5.78.0.a and libcprover.5.79.0.a and everything worked fine. But of course, there's no guarantee that even a weekly release change is going to work.

I can try linking it against an even earlier version to see what happens, but based on behaviour I have observed before, if this is not possible, the most likely outcome is a linking error.