Add instrumentation details to each README.md

[breedx-splk]

New users have no quick/easy way to determine what telemetry is provided by the various instrumentations here. This is a tracking issue and proposal to add specific details about the telemetry generated by each instrumentation.

For each instrumentation module, there should be a corresponding README.md file that provides:

• a description what the instrumentation does
• whether it is enabled by default via the agent
• how to configure it
• specific details about the instrumentation it provides.

Here is an instrumentation checklist that should be complete before this issue can be closed:

• [x] Activity (#750)
• [x] ANR (application not responding) (#787)
• [x] Crash reporting (#788)
• [ ] Fragment
• [ ] HttpUrlConnection
• [ ] Network (#789)
• [ ] OkHttp
• [x] Session (covered in #719)
• [x] SlowRendering
• [ ] Startup
• [ ] Volley

[magda-woj]

@breedx-splk I'd love to take on some of those (e.g. Fragment, Https, Slow Rendering?)

[breedx-splk]

@breedx-splk I'd love to take on some of those (e.g. Fragment, Https, Slow Rendering?)

Great! Thanks. I'll stay away from Fragment then while you take it.

[marcschaeferger]

@breedx-splk With PR #1242 this should be completed

[breedx-splk]

Thanks everyone!