docs: Updated README with `trace` endpoints & requirements note (#872)

Updated the sidecar README with :  

- The `trace` endpoints information and how to get access to them.
- Hardware requirements for sidecar (related to memory and required disk space).
- Specs when running sidecar and also a node in the same machine.
- Related benchmarks.

Co-authored-by: Zeke Mostov <[email protected]>
Co-authored-by: Tarik Gul <[email protected]>