Add sanic instrumentation

[srikanthccv]

@codeboten, will do!

Originally posted by @sid-maddy in open-telemetry/opentelemetry-python#1929 (reply in thread)

[srikanthccv]

@sid-maddy Created the issue for visibility. Please comment and will assign you.

[srikanthccv]

And also make sure to read these general guidelines before you start the work https://github.com/open-telemetry/opentelemetry-python-contrib/blob/main/CONTRIBUTING.md#guideline-for-instrumentations.

[ozancaglayan]

Hi,

Are other plugins supposed to generate some metrics for Sanic services or is this PR still relevant? I tried with one now but I only get a few asyncio metrics and the system/cpython ones. Don't get to see API call ones for example.

Thanks