Update and change Japanese translation

・Follow-up the PR #3411(Update Readme.fonts about Kana), Remove "who really..." strings. I had forgotten it.
・Add readable translated strings in comment
・Add Japanese translation.
  MSG_LCD_ENDSTOPS "エンドストップ"
  (utf8 version only. Because non-utf8 version ("ｴﾝﾄﾞｽﾄｯﾌﾟ") over 8 characters)
・Change translation.
  MSG_ACC "カソクド mm/s2"
  MSG_ACC "\xb6\xbf\xb8\xc4\xde mm/s2" ("ｶｿｸﾄﾞ mm/s2")

Follow the PR #3242.

In all these cases we want the axis to be homed. If we could have lost
some steps is secondary.

Reenables homing seperate axis with DISABLE_X / DISABLE_Y true.

Following up on #3231

documentation/LCDLanguageFont.md moved to http://www.marlinfirmware.org/ at commit 12d0983757,
but http://www.marlinfirmware.org/ isn't working.

Keep "astyled" reformatting

Apply `ENABLED` / `DISABLED` macros to language-related files.

* Added MSG_END_HOUR and MSG_END_MINUTE labels to all language files.
* Available translations:
  EN, FR, DE, ES, IT, PT, PT-BR.

Automatic selection was to unflexible.

Updated documentation

Updated language files to new logic and documentation.

Updated bdf2u8g.exe

And made falback to kana work.