Feat/otlp exporter bytes support

[NesterovYehor]

This PR adds support for the BYTES attribute type in the OTLP exporters.

[codecov]

Codecov Report

❌ Patch coverage is 87.71930% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.6%. Comparing base (2ffde5a) to head (f0596a1).

Files with missing lines	Patch %	Lines
log/keyvalue.go	0.0%	3 Missing ⚠️
attribute/internal/attribute.go	83.3%	1 Missing and 1 partial ⚠️
attribute/internal/xxhash/xxhash.go	50.0%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #8042     +/-   ##
=======================================
- Coverage   81.6%   81.6%   -0.1%     
=======================================
  Files        304     304             
  Lines      23452   23509     +57     
=======================================
+ Hits       19141   19186     +45     
- Misses      3928    3937      +9     
- Partials     383     386      +3     

Files with missing lines	Coverage Δ
attribute/hash.go	92.0% <100.0%> (+0.5%)	⬆️
attribute/key.go	100.0% <100.0%> (ø)
attribute/kv.go	100.0% <100.0%> (ø)
attribute/type_string.go	60.0% <ø> (ø)
attribute/value.go	92.6% <100.0%> (+0.7%)	⬆️
...otlp/otlplog/otlploggrpc/internal/transform/log.go	96.1% <100.0%> (+<0.1%)	⬆️
...otlp/otlplog/otlploghttp/internal/transform/log.go	96.1% <100.0%> (+<0.1%)	⬆️
...ric/otlpmetricgrpc/internal/transform/attribute.go	96.7% <100.0%> (+0.1%)	⬆️
...ric/otlpmetrichttp/internal/transform/attribute.go	96.7% <100.0%> (+0.1%)	⬆️
...tlp/otlptrace/internal/tracetransform/attribute.go	96.8% <100.0%> (+0.1%)	⬆️
... and 3 more

... and 3 files with indirect coverage changes

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