Support ios to default keymap (#3118)

Support ios to default keymap (#3118)

* add some comment about Helix customize and auto-setup RGBLIGHT_LIMIT_VAL

* add define USB_MAX_POWER_CONSUMPTION

* Helix keyboard OLED, RGBLIGHT enable/disable control integrate into rules.mk

rules.mk: add 4 Variables for compile control.

   # Helix keyboard customize
   # you can edit follows 4 Variables
   #  jp: 以下の4つの変数を必要に応じて編集します。
   OLED_ENABLE = no            # OLED_ENABLE
   LED_BACK_ENABLE = no        # LED backlight (Enable WS2812 RGB underlight.)
   LED_UNDERGLOW_ENABLE = no   # LED underglow (Enable WS2812 RGB underlight.)
   LED_ANIMATIONS = yes        # LED animations

config.h: auto set RGBLED_NUM by HELIX_ROWS and rules.mk's define

* HELIX_ROWS define move from config.h to rules.mk

* add readme.md

* rename readme.md to readme_jp.md

* add readme.md and modify readme_jp.md

* change helix/ssd1306.c for select glcdfont.c position

* add variable LOCAL_GLCDFONT into each keymaps rules.mk

* Add iPhone/iPad LED support to Helix default keymap

* add Freggy keymap

* adjust the delay of serial.c

* change readme

* renumber _ADJUST for shrink program size