c/p PSTR attribute from Core files
dostring declaration with a macro instead of a scary looking boilerplate
saves varying amount of code space, mostly deals with our key and cmd strings
- clean-up comparison routines and get rid of most of the casts
- reduces total number of calls to terminalRegisterCommand
replace with a func accepting list of commands, which in
turn get instantiated as constexpr PROGMEM arrays
- reduce ram fragmentation, since we don't need to alloc as much
- reduce flash consumption b/c of lambda -> standalone func conversion
sync and async dns functions for both terminal and this
both use callbacks with IPAddress helper instead of using ip_addr_t
(at least, for now. seems like it is in need of our own wrapper, too)
