Add support for the the Lakeshore 336 Temperature Controller

[trappitsch]

Note that this is by far not a complete implementation, but rather a starting point incorporating the functionality I need right now.

• first iteration of a working instrument to query the temperature for each channel
• add tests
• fmt

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.25000% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.60%. Comparing base (d569ea4) to head (8af96a9).

Files with missing lines	Patch %	Lines
lakeshore/lakeshore_336/src/lib.rs	78.94%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #12      +/-   ##
==========================================
- Coverage   86.20%   85.60%   -0.61%     
==========================================
  Files          15       17       +2     
  Lines         464      528      +64     
==========================================
+ Hits          400      452      +52     
- Misses         64       76      +12     

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