Move drsyscall to DynamoRIO

drsyscall is currently part of Dr. Memory Framework (DRMF) which is not part of DynamoRIO.

For DynamoRIO clients to use the functionalities provided by drsyscall, we need to move drsyscall to DynamoRIO similar to drwrap and drutil.

This will be done in multiple steps:

1. Add drsyscall code to dynamorio
- Clang-format: after move
- Update LGPL license list in DR top level license file to include drsyscall with drwrap+drutil
- Tests outside of drsyscall/ dir: have to move separately
2. Remove drsyscall from drmemory
- Fix up any hardcoded include paths in drmemory
- Update drmemory cmake code to find library from dynamorio
- Remove drsyscall from “DRMF” library docs/mentions