also, clean-up PGM_P usage and just use `const char*` instead

* ws: clean-up wsPost implementation

- explain ourselves
- re-do consts, fix locality
- fix shadowing in ctors
- more consistent naming
- timeout for messages

* save 16 bytes temporary

* reference reference

- general conversion from .ino modules into a separate .cpp files
- clean-up internal headers, place libraries into .h. guard .cpp with _SUPPORT flags 
- fix some instances of shared variables instead of public methods
- tweak build system to still build a single source file via os environment variable ESPURNA_BUILD_SINGLE_SOURCE

* Config: remove prototypes.h

* fixup order

* word

* add missing

* fix warning while still using .ino

* bad at c/p;

* Test: check core feature build

* order

* add missing