you can debug nuttx through any transport layer (serial port, network etc.),
currently supports the following functions:
1. Read and write registers
2. Read and write memory
3. Switch thread and read stack information
Future support plans:
1. Support breakpoint, watch point (requires architecture support).
related information:
https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
Signed-off-by: anjiahao <anjiahao@xiaomi.com>