Move Prometheus set up and use to a separate document for reuse across multiple tutorials.

[mkbhanda]

Content in https://github.com/srajabos/docs/blob/buf-163/tutorial/ChatQnA/ChatQnA_Guide.rst
@preethivenkatesh what do you think?

[yinghu5]

Hi @mkbhanda @preethivenkatesh @alexsin368 @louie-tsai and doc team, please help to consider [remind]

[louie-tsai]

agreed.
Most of the instructions should be similar among examples, and we will enable those telemetry support via docker compose for users. also, the contents in the doc are out of date now. most of setup instructions are not needed after this PR opea-project/GenAIExamples#1623

[louie-tsai]

addressing this request in #350

[yinghu5]

Hi @mkbhanda @louie-tsai thank you very much for raising and addressing the issue, which make the tutorial well originized.
https://opea-project.github.io/latest/tutorial/OpenTelemetry/OpenTelemetry_OPEA_Guide.html. closed as completed.