Introduce new 75_ansi standard layout (#3738)

* introduce new layout 75_ansi

* use the new 75_ansi layout for my octagon v2

layouts/default/75_ansi/default_75_ansi/keymap.c

@@ -0,0 +1,12 @@
+#include QMK_KEYBOARD_H
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+    /* layer 0: qwerty */
+    [0] = LAYOUT_75_ansi(\
+        KC_ESC,  KC_F1,   KC_F2,  KC_F3,  KC_F4,  KC_F5,  KC_F6,  KC_F7,  KC_F8,  KC_F9,   KC_F10,  KC_F11,  KC_F12,  KC_PSCR, KC_PAUS, KC_DEL,
+        KC_GRV,  KC_1,    KC_2,   KC_3,   KC_4,   KC_5,   KC_6,   KC_7,   KC_8,   KC_9,    KC_0,    KC_MINS, KC_EQL,  KC_BSPC, KC_HOME,
+        KC_TAB,  KC_Q,    KC_W,   KC_E,   KC_R,   KC_T,   KC_Y,   KC_U,   KC_I,   KC_O,    KC_P,    KC_LBRC, KC_RBRC, KC_BSLS, KC_PGUP,
+        KC_CAPS, KC_A,    KC_S,   KC_D,   KC_F,   KC_G,   KC_H,   KC_J,   KC_K,   KC_L,    KC_SCLN, KC_QUOT, KC_ENT,  KC_PGDN,
+        KC_LSFT, KC_Z,    KC_X,   KC_C,   KC_V,   KC_B,   KC_N,   KC_M,   KC_COMM, KC_DOT, KC_SLSH, KC_RSFT,          KC_UP,   KC_END,
+        KC_LCTL, KC_LGUI, KC_LALT,                KC_SPC,                                  KC_RALT, KC_RGUI, KC_RCTL, KC_LEFT, KC_DOWN, KC_RGHT)
+    };

layouts/default/75_ansi/layout.json

@@ -0,0 +1,6 @@
+[{a:7},"","","","","","","","","","","","","","","",""],
+["","","","","","","","","","","","","",{w:2},"",""],
+[{w:1.5},"","","","","","","","","","","","","",{w:1.5},"",""],
+[{w:1.75},"","","","","","","","","","","","",{w:2.25},"",""],
+[{w:2.25},"","","","","","","","","","","",{w:1.75},"","",""],
+[{w:1.25},"",{w:1.25},"",{w:1.25},"",{w:6.25},"","","","","","",""]

layouts/default/75_ansi/readme.md

@@ -0,0 +1,3 @@
+# 75_ansi
+
+    LAYOUT_75_ansi