Rename some internal funcs to allow the oc to new structs to reuse the names

[bogdandrutu]

Updates #1657

[codecov]

Codecov Report

Merging #1664 into master will decrease coverage by 0.02%.
The diff coverage is 94.11%.

@@            Coverage Diff             @@
##           master    #1664      +/-   ##
==========================================
- Coverage   92.24%   92.21%   -0.03%     
==========================================
  Files         262      262              
  Lines       18765    18761       -4     
==========================================
- Hits        17309    17301       -8     
- Misses       1042     1044       +2     
- Partials      414      416       +2     

Impacted Files	Coverage Δ
translator/internaldata/oc_to_old_metrics.go	88.88% <86.95%> (-0.23%)	⬇️
translator/internaldata/old_metrics_to_oc.go	91.54% <100.00%> (ø)
receiver/otlpreceiver/otlp.go	91.66% <0.00%> (-2.78%)	⬇️
translator/internaldata/resource_to_oc.go	87.03% <0.00%> (-1.86%)	⬇️

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