chore: Move agent availability to Account level (#3074)

- Move agent availability to the account level

swagger/paths/application/inboxes/create.yml

@@ -0,0 +1,50 @@
+post:
+  tags:
+    - Inbox
+  operationId: inboxCreation
+  summary: Create an inbox
+  description: You can create more than one website inbox in each account
+  parameters:
+    - $ref: '#/parameters/account_id'
+    - name: data
+      in: body
+      required: true
+      schema:
+        type: object
+        properties:
+          name:
+            type: string
+            description: The name of the inbox
+          avatar:
+            type: file
+            description: File for avatar image
+          channel:
+            type: object
+            properties:
+              type:
+                type: string
+                enum: ['web_widget']
+              website_url:
+                type: string
+                description: URL at which the widget will be loaded
+              welcome_title:
+                type: string
+                description: Welcome title to be displayed on the widget
+              welcome_tagline:
+                type: string
+                description: Welcome tagline to be displayed on the widget
+              agent_away_message:
+                type: string
+                description: A message which will be sent if there is not agent available. This is not available if agentbot is connected
+              widget_color:
+                type: string
+                description: A Hex-color string used to customize the widget
+  responses:
+    200:
+      description: Success
+      schema:
+        $ref: '#/definitions/inbox'
+    404:
+      description: Inbox not found
+    403:
+      description: Access denied