[Keyboard] AJisai74 (#10021)

* Add keyboard ajisai74

Add ajisai74 keyboard.

A 74 keys ANSI/JIS Layout keyboard.
Salicylic-acid3

* Update keyboards/ajisai74/keymaps/salicylic/keymap.c

* Update keyboards/ajisai74/keymaps/via/keymap.c

* Update keyboards/ajisai74/keymaps/via/keymap.c

* Update keyboards/ajisai74/rules.mk

* Update keyboards/ajisai74/rev1/rev1.h

* Update keyboards/ajisai74/keymaps/default/keymap.c

* Update keyboards/ajisai74/keymaps/default/keymap.c

* Update keyboards/ajisai74/keymaps/jis/keymap.c

* Keymap update

Fixed an unnecessary symbol at the end of the file.

* Update keyboards/ajisai74/readme.md

* Update keyboards/ajisai74/rev1/config.h

* Delete Rev1 directory

I removed the directory because I don't have any plans to update now.

* Update keyboards/ajisai74/rules.mk

* Added copyright

Added copyright to all files.

* Update keyboards/ajisai74/ajisai74.h

keyboards/ajisai74/readme.md

@@ -0,0 +1,17 @@
+# AJisai74
+
+![ajisai74](https://cdn-ak.f.st-hatena.com/images/fotolife/S/Salicylic_acid3/20200812/20200812214740.png)
+
+This is 74 keys Custom keyboard.
+
+* Keyboard Maintainer: [Salicylic_acid3](https://github.com/Salicylic-acid3)
+* Hardware Supported: AJisai74 PCB, Pro Micro
+* Hardware Availability: [PCB & Case Data](https://github.com/Salicylic-acid3/PCB_Data), [Booth Shop](https://salicylic-acid3.booth.pm/items/2291877)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make ajisai74:default
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+[Build guide](https://salicylic-acid3.hatenablog.com/entry/ajisai74-build-guide)