* Cleanup the component docs
Mostly minor cleanup, clarification, or slight restructuring. Added
repository information for instrumentation libraries to compliment #334
* Address feedback
* Add more concepts
- Merge docs and overview documentation into new data sources page
- Add a what is OpenTelemetry page
- Move common instrumentation documentation to new instrumenting page
- Add a data collection page
Also move collector introduction section of getting started guide to
main collector page.
Severin Neumann