* Add changes to TCK to support Rust Test Agent for Register_and_Send and register_and_unregister

Co-Authored-By: sagarsshah <157176449+sagarsshah@users.noreply.github.com>

Sagar and I have taken in the comments from Pete's PR review and addressed most of them in this commit. Mainly:
* Refactored utils.rs
* Removed extension trait for utransport
* Aligned names to rust coding standard
* Ran rustfmt on all files
* Ran clippy on all files: we addressed most of the clippy issues, but some will require more intense refactoring
* Minor fixes and idiomatic cleanup

Co-Authored-By: sagarsshah <157176449+sagarsshah@users.noreply.github.com>

Need to remove duplicate code that is no longer used.

Aligning the utransport_socket with recommendations from Pete. Instead of importing the utransport_socket.rs, we are now making it into a library crate.

We went through the large majority of issues presented in the PR Review, including:
* removing almost all expects and unwraps
* changing many method names to match standards
* reduce size of many methods through simplification and reorganization

Notes for reviewer:
* One 'expect' remains [main.rs, line 71]. would appreciate advice on how to remove that
* One clippy error remains. It's regarding holding the socket across async calls.
* A few unwraps remain, but those are mostly handled except for one regarding commstatus

Co-Authored-By: sagarsshah <157176449+sagarsshah@users.noreply.github.com>

Fix last clippy issue related to holding mutex across awaits (testagent.rs, line 225--)
Remove last expect for commstatus
Change wrapperu_message var name to wrapper_umessage
Add rust to new spawning paradigm in tck_step_implementations.py

* Change dbg! to using log debug! crate.
* Changed "loop" in test agent to "while"
* Remove some comments

* update licenses
* remove get_ustatus_code
* add err_string to reuse error msgs
* change signature of parse_uauthority
* remove commented code
* formatting on lib.rs
* remove panic references since doesn't panic

Co-Authored-By: Pete LeVasseur <11622119+plevasseur@users.noreply.github.com>

* Change specialfields to default
* Add "not implemented" to notification type
* Some fixes to debug msgs and comments

* Remove special_fields from the uattributes deserializer