otlp: Move otlptranslator package from prom/prom to here

[ywwg]

For eventual import by otel collector

[ArthurSens]

Nice, thanks for starting this!

I believe we agreed on just moving the "name translator" and not the remotewrite translator. I can't remember exactly why we came to this agreement though 🤔

[ywwg]

If that was an agreement between you and me, I think that was based on a misunderstanding I had about the code arrangement. Based on the diffing I've done, the translators are pretty close together between prom and otel-col. I think what I'll do is try to work ahead a few PRs and confirm that otel will work when linked against this code. If not then we can avoid rolling things back

[ArthurSens]

If that was an agreement between you and me

No, it was within the otel-prom SIG call. It was probably captured in this meeting note's entry, but, if after digging deeper into the code it might sound too difficult, we can re-think that decision