Add premade layouts for Numpad 4x4, Numpad 5x4, Ortho 5x4, and Planck MIT (#3139)

Fix EOF on Planck MIT layout.json

Cleanup ortho_5x4 layout.json

layouts/default/numpad_4x4/default_numpad_4x4/keymap.c

@@ -0,0 +1,11 @@
+#include QMK_KEYBOARD_H
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+  [0] = LAYOUT_numpad_4x4(
+    KC_P7,   KC_P8,   KC_P9,   KC_PPLS, \
+    KC_P4,   KC_P5,   KC_P6,            \
+    KC_P1,   KC_P2,   KC_P3,   KC_PENT, \
+        KC_P0,        KC_PDOT           \
+  ),
+
+};