Introduce a list of image mime types we can support as images

E.g. TIFF will now be handled as a generic file, not image, even though it has mime prefix "image/"

src/components/Profile.vue

@@ -33,7 +33,7 @@
               type="file"
               name="avatar"
               @change="handlePickedAvatar($event)"
-              accept="image/*"
+              :accept="supportedImageTypes"
               class="d-none"
             />
           </v-avatar>