feat(apps): Shopify Integration (#11101)

This PR adds native integration with Shopify. No more dashboard apps.
The support agents can view the orders, their status and the link to the
order page on the conversation sidebar.

This PR does the following: 
- Create an integration with Shopify (a new app is added in the
integrations tab)
- Option to configure it in SuperAdmin
- OAuth endpoint and the callbacks.
- Frontend component to render the orders. (We might need to cache it in
the future)
---------

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

spec/models/integrations/app_spec.rb

@@ -51,17 +51,38 @@ RSpec.describe Integrations::App do
       end
     end
 
-    context 'when the app is linear' do
-      let(:app_name) { 'linear' }
+    context 'when the app is shopify' do
+      let(:app_name) { 'shopify' }
 
-      it 'returns true if the linear integration feature is disabled' do
+      it 'returns true if the shopify integration feature is enabled' do
+        account.enable_features('shopify_integration')
+        allow(GlobalConfigService).to receive(:load).with('SHOPIFY_CLIENT_ID', nil).and_return('client_id')
+        expect(app.active?(account)).to be true
+      end
+
+      it 'returns false if the shopify integration feature is disabled' do
+        allow(GlobalConfigService).to receive(:load).with('SHOPIFY_CLIENT_ID', nil).and_return('client_id')
         expect(app.active?(account)).to be false
       end
 
-      it 'returns false if the linear integration feature is enabled' do
+      it 'returns false if SHOPIFY_CLIENT_ID is not present, even if feature is enabled' do
+        account.enable_features('shopify_integration')
+        allow(GlobalConfigService).to receive(:load).with('SHOPIFY_CLIENT_ID', nil).and_return(nil)
+        expect(app.active?(account)).to be false
+      end
+    end
+
+    context 'when the app is linear' do
+      let(:app_name) { 'linear' }
+
+      it 'returns false if the linear integration feature is disabled' do
+        expect(app.active?(account)).to be false
+      end
+
+      it 'returns true if the linear integration feature is enabled' do
         account.enable_features('linear_integration')
         account.save!
-
+        allow(GlobalConfigService).to receive(:load).with('LINEAR_CLIENT_ID', nil).and_return('client_id')
         expect(app.active?(account)).to be true
       end
     end