In order to improve security around the command processing, I plan to
upgrade the communication protocol to use a fixed structure with an
optional payload. As a first pass on this, I added a script to generate
the IDs automatically from the configuration, as well as a script to map
the module names and log levels to integer IDs.
This also replaces the manual lmap_* and array_get_index lookup tables,
so I don't have to always deal with creating an entry in constants.h and
command.c and making sure they are in sync.
