[Grbl_Esp32 PR#421] Fix compile problems with different ENABLE_s

Some WebUI commands were present even when the
relevant ENABLE_ was not defined, This corrects
that and make the presence/absense of the various
commands correspond to the old code with different
combinations of web-related enables in config.h

To make things easier to find, the order of the
web command functions in the file now corresponds
with the listed order of the command names.