Use OTel SDK's self-diagnostics - managed code - document troubleshooting

[pellared]

We should use OTel SDK's self-diagnostics for internal logging.

[nrcventura]

One thing that I do not like about this approach, based on the current functionality in that feature, is that it requires someone to drop a file in a particular location to get the log files generated. The problems that I have seen people experience with that approach are the following.

1. Figuring out which directory to place this special file in
2. Having enough permissions to get a file added to that directory

If we had the ability to control these log files via environment variables, I think that would improve the experience, and simplify things for us and our users.

[Kielek]

Only describe in troubleshooting doc how to do it.

[lachmatt]

SdkSelfDiagnosticsEventListener fulfills similar purpose.
I think with recent logging improvements to internal logger, this is no longer needed.

[Kielek]

Closing per previous comment.