Added microscope settings placeholder

<template>

  <div id="paneSettings">

    <h3>Settings</h3>

    <ul uk-accordion="multiple: true">

      <li>

        <a class="uk-accordion-title" href="#">App settings</a>

        <div class="uk-accordion-content">

          <div class="uk-child-width-1-2" uk-grid>

            <p><label><input v-model="disableStream" class="uk-checkbox" type="checkbox"> Disable stream</label></p>

            <p><label class="uk-disabled"><input v-model="autoGpuPreview" class="uk-checkbox" type="checkbox"> GPU preview</label></p>

          </div>

        </div>

      </li>

      <li>

        <a class="uk-accordion-title" href="#">Microscope settings</a>

        <div class="uk-accordion-content">

          <div class="uk-placeholder uk-text-center">Microscope config coming soon...</div>

      </li>

    </ul>

  </div>

</template>