chore: Custom Roles to manage permissions [ UI ] (#9865)

In admin settings, this Pr will add the UI for managing custom roles (
ref: https://github.com/chatwoot/chatwoot/pull/9995 ). It also handles
the routing logic changes to accommodate fine-tuned permissions.

---------

Co-authored-by: Pranav <pranavrajs@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/constants/permissions.js

@@ -0,0 +1,53 @@
+export const AVAILABLE_CUSTOM_ROLE_PERMISSIONS = [
+  'conversation_manage',
+  'conversation_unassigned_manage',
+  'conversation_participating_manage',
+  'contact_manage',
+  'report_manage',
+  'knowledge_base_manage',
+];
+
+export const ROLES = ['agent', 'administrator'];
+
+export const CONVERSATION_PERMISSIONS = [
+  'conversation_manage',
+  'conversation_unassigned_manage',
+  'conversation_participating_manage',
+];
+
+export const MANAGE_ALL_CONVERSATION_PERMISSIONS = 'conversation_manage';
+
+export const CONVERSATION_UNASSIGNED_PERMISSIONS =
+  'conversation_unassigned_manage';
+
+export const CONVERSATION_PARTICIPATING_PERMISSIONS =
+  'conversation_participating_manage';
+
+export const CONTACT_PERMISSIONS = 'contact_manage';
+
+export const REPORTS_PERMISSIONS = 'report_manage';
+
+export const PORTAL_PERMISSIONS = 'knowledge_base_manage';
+
+export const ASSIGNEE_TYPE_TAB_PERMISSIONS = {
+  me: {
+    count: 'mineCount',
+    permissions: [...ROLES, ...CONVERSATION_PERMISSIONS],
+  },
+  unassigned: {
+    count: 'unAssignedCount',
+    permissions: [
+      ...ROLES,
+      MANAGE_ALL_CONVERSATION_PERMISSIONS,
+      CONVERSATION_UNASSIGNED_PERMISSIONS,
+    ],
+  },
+  all: {
+    count: 'allCount',
+    permissions: [
+      ...ROLES,
+      MANAGE_ALL_CONVERSATION_PERMISSIONS,
+      CONVERSATION_PARTICIPATING_PERMISSIONS,
+    ],
+  },
+};