Settings backup/restore + small fixes

Another stepping stone for settings sync, should enable easier debug for us and manual sync solution for the impatient. Also should make wiping localstorage less of a problem since it also backs up user highlights which don't have proper UI for them.

Major:

• Changed ImportExport component into a service since it's mostly logic/direct DOM-manip, not much of markup going on, makes it more reusable and avoid mess with slots
• Implemented settings save/restore function
  • New dropdown button in modal footer: save, save with theme, restore
  • Settings saved with array version - current version [1, 0] - works similarly to semver but in array, for future-proofing it will refuse to load settings with major version != 1 (i.e. [2, 0]) but will work different minor version, i.e. [1, 1].
  • Separate control for theme saving since theme data is quite heavy.
    • For future we might add dialog box asking if user wants to import theme as well if it's present
  • Restoring goes over supported properties and updates them using setOption with data found in file. Minor stuff:
• one more fix for "p's broken theme" fucking up theme editor and making it mostly unusable
• changed "Peek"/"Close" buttons to use icons instead, feels a bit more natural and less confusing given that there are now button in footer too.
• panel footers no longer use panel header colors, it just looked silly and didn't really work with some themes (redmond), cleaned up their styles a bit

src/components/settings_modal/tabs/theme_tab/theme_tab.vue

@@ -48,46 +48,51 @@
             </template>
           </div>
         </div>
-        <ExportImport
-          :export-object="exportedTheme"
-          :export-label="$t(&quot;settings.export_theme&quot;)"
-          :import-label="$t(&quot;settings.import_theme&quot;)"
-          :import-failed-text="$t(&quot;settings.invalid_theme_imported&quot;)"
-          :on-import="onImport"
-          :validator="importValidator"
-        >
-          <template slot="before">
-            <div class="presets">
-              {{ $t('settings.presets') }}
-              <label
-                for="preset-switcher"
-                class="select"
+        <div class="top">
+          <div class="presets">
+            {{ $t('settings.presets') }}
+            <label
+              for="preset-switcher"
+              class="select"
+            >
+              <select
+                id="preset-switcher"
+                v-model="selected"
+                class="preset-switcher"
               >
-                <select
-                  id="preset-switcher"
-                  v-model="selected"
-                  class="preset-switcher"
+                <option
+                  v-for="style in availableStyles"
+                  :key="style.name"
+                  :value="style"
+                  :style="{
+                    backgroundColor: style[1] || (style.theme || style.source).colors.bg,
+                    color: style[3] || (style.theme || style.source).colors.text
+                  }"
                 >
-                  <option
-                    v-for="style in availableStyles"
-                    :key="style.name"
-                    :value="style"
-                    :style="{
-                      backgroundColor: style[1] || (style.theme || style.source).colors.bg,
-                      color: style[3] || (style.theme || style.source).colors.text
-                    }"
-                  >
-                    {{ style[0] || style.name }}
-                  </option>
-                </select>
-                <FAIcon
-                  class="select-down-icon"
-                  icon="chevron-down"
-                />
-              </label>
-            </div>
-          </template>
-        </ExportImport>
+                  {{ style[0] || style.name }}
+                </option>
+              </select>
+              <FAIcon
+                class="select-down-icon"
+                icon="chevron-down"
+              />
+            </label>
+          </div>
+          <div class="export-import">
+            <button
+              class="btn button-default"
+              @click="importTheme"
+            >
+              {{ $t(&quot;settings.import_theme&quot;) }}
+            </button>
+            <button
+              class="btn button-default"
+              @click="exportTheme"
+            >
+              {{ $t(&quot;settings.export_theme&quot;) }}
+            </button>
+          </div>
+        </div>
       </div>
       <div class="save-load-options">
         <span class="keep-option">