Consider removing the materialdesign CDN image dependencies

[E3V3A]

There is no good reason to keep the module having to download the material design icons, every time they are needed. It also prevent the module to display properly if:

• You have firewalled / adblocker not allowing the cdn site
• You do not have an internet connection

Here is the line that does the loading:

  loadCSS: function() {
    var css = [{
        id:   'materialDesignIcons',
        href: 'https://cdn.materialdesignicons.com/2.0.46/css/materialdesignicons.min.css',
    }]

So to accomplish this we need to download the images and keep them in ./images/ (?). The icons in question are specified here (and possible in other places).

  getDom : function() {
    var wrapper = document.createElement("div")
    wrapper.className = "ASSTNT"
    var iconDom = document.createElement("div")
    iconDom.className = "mdi status " + this.status + " "
    switch(this.status) {
      case 'INITIALIZED':
        iconDom.className += "mdi-microphone-outline"
        break
      case 'HOTWORD_STARTED':
        iconDom.className += "mdi-microphone"
        break
      case 'HOTWORD_DETECTED':
        iconDom.className += "mdi-microphone"
        break
      case 'ASSISTANT_STARTED':
        iconDom.className += "mdi-google-assistant"
        break
      case 'ASSISTANT_SPEAKING':
        iconDom.className += "mdi-google-assistant"
        break
      case 'COMMAND_STARTED':
        iconDom.className += "mdi-apple-keyboard-command"
        break
      case 'COMMAND_LISTENED':
        iconDom.className += "mdi-apple-keyboard-command"
        break
      case 'SPEAK_STARTED':
        iconDom.className += "mdi-message-processing"
        break
      case 'SPEAK_ENDED':
        iconDom.className += "mdi-microphone"
        break
}