Support log appender/handler configuration

[codeboten]

Follow up from #20, users must have a way to specify hooking up log appenders/handlers to the logging provider.

The wiring up of appenders to the SDK seems more like an instrumentation concern than an SDK concern. I suggest we include that under the instrumentation section. I.e. something like:

sdk:
  ...
instrumentation:
  log_appenders:
    - name: log4j
    - name: logback

Originally posted by @jack-berg in #20 (comment)

[codeboten]

We may want to add this under a language-specific section:

sdk:
  ...
instrumentation:
  ...
java:
  log_appenders:
    - name: log4j
    - name: logback
python:
  log_handlers:
    - name: logging

[svrnm]

looks like those appenders are language specific, so the 2. would match that, although I am wondering if java, python etc are top level elements or if they should be sub-elements of sdk/instrumentation?

[codeboten]

there are some language specific options that apply to things outside of instrumentations, maybe a language section would work? For now we could always say they are top level elements and change it later

[svrnm]

there are some language specific options that apply to things outside of instrumentations, maybe a language section would work? For now we could always say they are top level elements and change it later

I would prefer a language or languageSpecific or similar parent element, because the list of languages is technically not limited and that makes me worry that there is eventually an issue.