Rust wrapper: support optional heap and dev_id parameters

[holtrop]

Description

Rust wrapper: support optional heap and dev_id parameters

Testing

How did you test?

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[holtrop]

retest this please

[devin-ai-integration]

🛟 Devin Lifeguard found 1 likely issues in this PR

• do-not-change-external-apis snippet snippet snippet snippet: Restore the original no-argument public functions (e.g., keep pub fn new() -> Result<Self,i32>) and have them internally call the newly-introduced extended versions (new_ex(heap, dev_id)) with default None/INVALID_DEVID values, while leaving the extended APIs as the new optional variants.

@holtrop
please take a look at the above issues which Devin flagged. Devin will not fix these issues automatically.

[gasbytes]

Minor documentation inconsistency, the rest LGTM.

I guess the only thing that comes to mind is probably we could add in the documentation of the heap argument that the pointer must remain valid for the lifetime of the object (?) though this is pretty niche and what constitute a valid heap argument.