feat: Add new sidebar for Chatwoot V4 (#10291)

This PR has the initial version of the new sidebar targeted for the next major redesign of the app. This PR includes the following changes

- Components in the `layouts-next` and `base-next` directories in `dashboard/components`
- Two generic components `Avatar` and `Icon`
- `SidebarGroup` component to manage expandable sidebar groups with nested navigation items. This includes handling active states, transitions, and permissions.
- `SidebarGroupHeader` component to display the header of each navigation group with optional icons and active state indication.
- `SidebarGroupLeaf` component for individual navigation items within a group, supporting icons and active state.
- `SidebarGroupSeparator` component to visually separate nested navigation items. (They look a lot like header)
- `SidebarGroupEmptyLeaf` component to render empty state of any navigation groups.

----

Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Pranav <pranavrajs@gmail.com>

app/javascript/dashboard/components/SidemenuIcon.vue

@@ -1,5 +1,7 @@
 <script>
+import { FEATURE_FLAGS } from 'dashboard/featureFlags';
 import { BUS_EVENTS } from 'shared/constants/busEvents';
+import { mapGetters } from 'vuex';
 import { emitter } from 'shared/helpers/mitt';
 
 export default {
@@ -9,6 +11,18 @@ export default {
       default: 'small',
     },
   },
+  computed: {
+    ...mapGetters({
+      accountId: 'getCurrentAccountId',
+      isFeatureEnabledonAccount: 'accounts/isFeatureEnabledonAccount',
+    }),
+    hasNextSidebar() {
+      return this.isFeatureEnabledonAccount(
+        this.accountId,
+        FEATURE_FLAGS.CHATWOOT_V4
+      );
+    },
+  },
   methods: {
     onMenuItemClick() {
       emitter.emit(BUS_EVENTS.TOGGLE_SIDEMENU);
@@ -17,8 +31,10 @@ export default {
 };
 </script>
 
+<!-- eslint-disable-next-line vue/no-root-v-if -->
 <template>
   <woot-button
+    v-if="!hasNextSidebar"
     :size="size"
     variant="clear"
     color-scheme="secondary"