Convert Saswell (Tuya) TRVs to v2

[prairiesnpr]

Proposed change

This converts the Saswell TRVs to v2. This does introduce a duplicate TuyaThermostatV2, but I intend to consolidate all TRVs to tuya_trv.py so this will resolve itself in a follow-on PR.

Additional information

Checklist

• The changes are tested and work correctly
• pre-commit checks pass / the code has been formatted using Black
• Tests have been added to verify that the new code works

[codecov]

Codecov Report

Attention: Patch coverage is 85.29412% with 5 lines in your changes missing coverage. Please review.

Project coverage is 90.74%. Comparing base (d9481d3) to head (60ca6da).
Report is 3 commits behind head on dev.

Files with missing lines	Patch %	Lines
zhaquirks/tuya/tuya_trv.py	85.29%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #3772      +/-   ##
==========================================
+ Coverage   90.40%   90.74%   +0.34%     
==========================================
  Files         320      320              
  Lines       10490    10427      -63     
==========================================
- Hits         9483     9462      -21     
+ Misses       1007      965      -42     

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