For pyocd debug, it appears the device under debug must be halted after
UPLOAD_LAUNCH_COMMANDS, or debugger will become abnormal.

This converts output to Intel HEX format unconditionally but to BIN
format just on demand for the following reasons:
1. Most flash programming tools support Intel HEX format, e.g. GDB
   load command.
2. Output can have large holes in addresses which BIN format cannot
   handle and can generate very large file.

This gives chance to adjust GDB commands MBED_UPLOAD_LAUNCH_COMMANDS
or MBED_UPLOAD_RESTART_COMMANDS for debug launch by implementing
mbed_adjust_upload_debug_commands cmake function.

With this adjustment, GDB load command changes to "load <app>.hex" from
just "load":
1. "Load" will load <app>.elf and is inappropriate for targets like
   bootloader or TF-M enabled which need to post-build process images.
2. "load <app>.bin" is not considered because GDB load command doesn't
   support binary format.

This enables generating GDB command line gdbinit file for single project
multiple application scenario. The gdbinit file name would be <app>.gdbinit
for distinct among multiple applications.