otel feature with tracing functionality only

[LikhithST]

as suggested in pull request #97 this PR contains only the tracing functionality without the context transfer between clients and the databroker

[SebastianSchildt]

@lukasmittag or @argerus please check if this is acceptable/non-invasive enough and if so approve. Would be nice to have basic OTEL support (we can still think about how to do the context transfer "nicer" in a follow up PR)

[codecov]

Codecov Report

Attention: Patch coverage is 55.31915% with 42 lines in your changes missing coverage. Please review.

Project coverage is 59.01%. Comparing base (2159d18) to head (a4d4955).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
databroker/src/lib.rs	0.00%	23 Missing ⚠️
databroker/src/open_telemetry.rs	0.00%	16 Missing ⚠️
databroker/src/grpc/kuksa_val_v1/val.rs	81.81%	2 Missing ⚠️
databroker/src/grpc/kuksa_val_v1/conversions.rs	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #119      +/-   ##
==========================================
- Coverage   59.49%   59.01%   -0.48%     
==========================================
  Files          33       34       +1     
  Lines       16070    15048    -1022     
==========================================
- Hits         9561     8881     -680     
+ Misses       6509     6167     -342     

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