Improves the tool lists in the top-level README.md and in the web home page:
- Adds a documentation page for drdisas (#4029 (closed)) and adds drdisas to the tool list.
- Splits the drcachesim huge page by upgrading each section into a separate page. Renames the top level to make it clear it's a general drmemtrace tracing framework and not just a cache simulator. Lists the main trace analysis tools separately at the top level.
- Adds references to 3 external tools: the Arm Instruction Emulator, WinAFL, and DrCCTProf.
- Adds a page for the other samples to the Available Tools menu.
Issue: #4111, #4029 (closed) Fixes #4029 (closed)