feat(debugging): move gdbinit generation to CMake

This feature is useful for 3rd-party software to run GDB with predefined
options that described in project_description.json file

allow to pass custom options to "idf.py gdb":

  --gdb-commands: command line arguments for gdb. (without changes)
  -ex: pass command to gdb.
  -x: pass gdbinit file to gdb. Alias for old --gdbinit command

tools/cmake/idf.cmake

@@ -48,7 +48,9 @@ if(NOT __idf_env_set)
     include(ldgen)
     include(dfu)
     include(version)
+    include(gdbinit)
     include(prefix_map)
+    include(openocd)
 
     __build_init("${idf_path}")