Migrate build target markers to keyboard.json - S (#23532)

keyboards/smallkeyboard/keyboard.json

@@ -8,6 +8,13 @@
     "pid": "0x736B",
     "device_version": "0.0.1"
   },
+  "features": {
+    "bootmagic": true,
+    "extrakey": true,
+    "mousekey": true,
+    "nkro": false,
+    "rgb_matrix": true
+  },
   "rgb_matrix": {
     "animations": {
       "alphas_mods": true,

keyboards/smallkeyboard/rules.mk

@@ -1,16 +1 @@
-# Build Options
-#   change yes to no to disable
-#
-BOOTMAGIC_ENABLE = yes      # Enable Bootmagic Lite
-MOUSEKEY_ENABLE = yes       # Mouse keys
-EXTRAKEY_ENABLE = yes       # Audio control and System control
-CONSOLE_ENABLE = no        # Console for debug
-COMMAND_ENABLE = no         # Commands for debug and configuration
-NKRO_ENABLE = no            # Enable N-Key Rollover
-BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
-RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
-AUDIO_ENABLE = no           # Audio output
-
-RGB_MATRIX_ENABLE = yes
-
 RGB_MATRIX_SUPPORTED = yes