Support for customized logging

[crystalin]

Ideally, the library should allow the user to control how the logs are produced.
Here is the requirements we believe are needed for our parachain node:

• Support to log the request, including its payload*
• Support to log the response, including its payload* and the timing
• *Payload could be filtered (to include some fields, or based on the method used). The possibility to reduce the the content of the fields in the payout automatically (like an array of 1000 items displaying only the first and last item).

[librelois]

One possibility proposed by @dvdplm would be to integrate sc_tracing and allow users to inject their own tracing-subscriber.

[niklasad1]

This is partly fixed by #722

It adds a tracing span per method name with a limit just to truncate logs bigger than n characters.
What's is nice is that you can subscribe to just a method name that you are interested in instead of doing it globally with middleware (unless you want to recompile and have some filter).

But we'll add more details in the middleware too soon so we can pick either because tracing is a bit less flexible for users as the logging output is simply truncated.

[niklasad1]

Closed by #793

jsonrpsee has both "tracing spans" and middleware for you to customize your logging.