Rework CI workflows (#8688)

- split workflows into separate files to trigger by path
  this should help out documentation and boards / eboot / pkg files
  updates, since those *wont* trigger usual build stuff anymore
- build*.sh whatever merged into just common.sh and build.sh
  trigger different parity builds, mod % rem and allow to set .ino list
  through the environment variable
- removes unnecessary temporary files, try to use more pipes
  move remaining ones into cache dir instead of PWD
- remove legacy TRAVIS env vars, use ESP8266_ARDUINO prefix for config
- remove Windows path workarounds
- hardware/ and ide/ directories are set through envionment
  do not force specific paths, simplify builds on local machine
- sketch list is set through environment. expicit paths for Windows and
  macOS builders. platformio also gets a real shuffled list instead of
  mod and rem magic numbers
- detect root of the repo through git cli, not base{name,dir} or relative paths

libraries/DNSServer/examples/NAPTCaptivePortal/NAPTCaptivePortal.ino

@@ -80,6 +80,8 @@
 #include <ESP8266mDNS.h>
 #include <EEPROM.h>
 
+#include "WifiHttp.h"
+
 #define NAPT 1000
 #define NAPT_PORT 10
 

libraries/DNSServer/examples/NAPTCaptivePortal/WifiHttp.h

@@ -11,6 +11,10 @@
 // code there till it is correct then copy/paste back here. Then, you can move
 // comment boarders around until the C code is back in place.
 
+#pragma once
+
+#include <Arduino.h>
+
 #ifdef DEBUG_VIEW
 static const char configHead[] PROGMEM = R"EOF(
 <!--