Replace tasksubmitter with action-button

I've changed tasksubmitter to accept a "thing" and "action" rather than a single URL. This seems more in keeping with
propertyControl, and eliminates the need for loads of
computed properties.

I've also deleted (rather than just commenting out) chunks of the web app that are no longer in use. These may be
reinstated in the future - but we can get them from git
history. It's less confusing not to have vestigial
code in the repo.

This builds OK but is not, as yet, tested with hardware.

webapp/src/components/appContent.vue

@@ -7,7 +7,6 @@
     <!-- Initialisation modals -->
     <calibrationModal
       ref="calibrationModal"
-      :available-plugins="plugins"
       @onClose="enterApp()"
     ></calibrationModal>
     <!-- Vertical tab bar -->
@@ -41,22 +40,6 @@
           <hr v-if="item.divide" :key="'tab-divider-' + index" />
         </template>
 
-        <!-- For each plugin tab -->
-        <tabIcon
-          v-for="plugin in pluginsGuiList"
-          :key="plugin.id"
-          :tab-i-d="plugin.id"
-          :title="plugin.title"
-          :require-connection="plugin.requiresConnection"
-          :current-tab="currentTab"
-          :click-callback="updatePlugins"
-          @set-tab="setTab"
-        >
-          <span class="material-symbols-outlined">{{
-            plugin.icon || "extension"
-          }}</span>
-        </tabIcon>
-
         <tabIcon
           v-for="imjoyTab in imjoyTabs"
           :key="imjoyTab.id"
@@ -115,23 +98,6 @@
         <component :is="item.component"></component>
       </tabContent>
 
-      <!-- For each plugin tab -->
-      <tabContent
-        v-for="plugin in pluginsGuiList"
-        :key="plugin.id"
-        :tab-i-d="plugin.id"
-        :require-connection="plugin.requiresConnection"
-        :current-tab="currentTab"
-      >
-        <extensionContent
-          :forms="plugin.forms"
-          :frame="plugin.frame"
-          :web-component="plugin.wc"
-          :view-panel="plugin.viewPanel"
-          @reloadForms="updatePlugins()"
-        />
-      </tabContent>
-
       <tabContent
         v-for="imjoyTab in imjoyTabs"
         :key="imjoyTab.id"
@@ -166,19 +132,13 @@ import tabContent from "./genericComponents/tabContent";
 
 // Import new content components
 import navigateContent from "./tabContentComponents/navigateContent.vue";
-import captureContent from "./tabContentComponents/captureContent.vue";
 import slideScanContent from "./tabContentComponents/slideScanContent.vue";
 import backgroundDetectContent from "./tabContentComponents/backgroundDetectContent.vue";
 import viewContent from "./tabContentComponents/viewContent.vue";
 import settingsContent from "./tabContentComponents/settingsContent.vue";
-import extensionContent from "./tabContentComponents/extensionContent.vue";
 import aboutContent from "./tabContentComponents/aboutContent.vue";
 import loggingContent from "./tabContentComponents/loggingContent.vue";
-// ImJoy and the gallery are loaded asynchronously to allow them to be disabled if needed
-const galleryContent = () =>
-  import(
-    /* webpackChunkName: "gallery" */ "./tabContentComponents/galleryContent.vue"
-  );
+// ImJoy is loaded asynchronously to allow it to be disabled if needed
 const imjoyContent = () =>
   import(
     /* webpackChunkName: "imjoy" */ "./tabContentComponents/imjoyContent.vue"
@@ -197,12 +157,9 @@ export default {
     tabIcon,
     tabContent,
     navigateContent,
-    captureContent,
     slideScanContent,
     viewContent,
     settingsContent,
-    galleryContent,
-    extensionContent,
     calibrationModal,
     aboutContent,
     loggingContent,
@@ -211,7 +168,6 @@ export default {
   },
   data: function() {
     return {
-      plugins: [],
       currentTab: "view",
       bottomTabs: [
         {
@@ -235,25 +191,11 @@ export default {
   },
 
   computed: {
-    pluginsGuiList: function() {
-      // List of plugin GUIs, obtained from this.plugins values
-      var pluginGuis = [];
-      for (let plugin of Object.values(this.plugins)) {
-        if (plugin.meta.gui) {
-          pluginGuis.push(plugin.meta.gui);
-        }
-      }
-      return pluginGuis;
-    },
-
     tabOrder: function() {
       var ind = [];
       for (const tab of this.topTabs) {
         ind.push(tab.id);
       }
-      for (const plugin of this.pluginsGuiList) {
-        ind.push(plugin.id);
-      }
       for (const tab of this.bottomTabs) {
         ind.push(tab.id);
       }
@@ -272,11 +214,6 @@ export default {
           icon: "gamepad",
           component: navigateContent
         },
-        /*{
-          id: "gallery",
-          icon: "photo_library",
-          component: galleryContent
-        },*/
         {
           id: "slidescan",
           icon: "settings_overscan",
@@ -318,11 +255,7 @@ export default {
 
   created: function() {
     if (this.$store.getters.ready) {
-      // Update plugins
-      this.updatePlugins().then(() => {
-        // Start initialisation modals
-        this.startModals();
-      });
+      this.startModals();
     }
   },
 
@@ -342,19 +275,6 @@ export default {
   },
 
   methods: {
-    updatePlugins: function() {
-      /*return axios
-        .get(this.pluginsUri)
-        .then(response => {
-          this.plugins = response.data;
-        })
-        .catch(error => {
-          this.modalError(error); // Let mixin handle error
-        });*/
-      return new Promise(resolve => {
-        resolve({});
-      });
-    },
     setTab: function(event, tab) {
       if (!(this.currentTab == tab)) {
         this.currentTab = tab;