Module creation & registration now made a lot simpler. In essence,
each module file is now self-contained and only needs a
NODEMCU_MODULE(MYNAME, "myname", myname_map, luaopen_myname);
line to both be automatically recognised by the Lua initialization
as well as honor the LUA_USE_MODULES_MYNAME #define.
As per #810 & #796, only LUA_OPTIMIZE_MEMORY=2 & MIN_OPT_LEVEL=2 are
supported when building. This commit effects that limitation.
With this change modules/auxmods.h no longer needs to be updated for
every new module, nor do module writers need to cater for a hypothetical
LUA_OPTIMIZE_MEMORY < 2 scenario.