add 'button' support in custom menus

[Xelus22]

Add button support to the custom menus

https://github.com/the-via/reader/pull/28 in the-via/reader is also required

Tested with Hayabusa with this configuration

"menus": [
  {
    "label": "Lighting",
    "content": [
      {
        "label": "Backlight",
        "content": [
          {
            "label": "Test Button",
            "type": "button",
            "options": [34],
            "content": [ "id_caps_lock_enable", 0, 1 ]
          }
        ]
      }
    ]
  }
],

Tested and working with https://github.com/Xelus22/qmk_firmware/commit/ca7f6629eb52687f2a4fb93bc6462a099de518d5