docs: add comprehensive integration documentation for various services (#2999)

- Introduced detailed documentation for integrations including Asana, Box, ClickUp, GitHub, Gmail, Google Calendar, Google Sheets, HubSpot, Jira, Linear, Notion, Salesforce, Shopify, Slack, Stripe, and Zendesk.
- Updated main docs.json to include a new "Integration Docs" section, organizing the documentation for easy access.
- Each integration includes setup instructions, available actions, and example tasks to streamline user onboarding and usage.

docs/docs.json

@@ -266,6 +266,27 @@
               "enterprise/features/integrations"
             ]
           },
+          {
+            "group": "Integration Docs",
+            "pages": [
+              "enterprise/integrations/asana",
+              "enterprise/integrations/box",
+              "enterprise/integrations/clickup",
+              "enterprise/integrations/github",
+              "enterprise/integrations/gmail",
+              "enterprise/integrations/google_calendar",
+              "enterprise/integrations/google_sheets",
+              "enterprise/integrations/hubspot",
+              "enterprise/integrations/jira",
+              "enterprise/integrations/linear",
+              "enterprise/integrations/notion",
+              "enterprise/integrations/salesforce",
+              "enterprise/integrations/shopify",
+              "enterprise/integrations/slack",
+              "enterprise/integrations/stripe",
+              "enterprise/integrations/zendesk"
+            ]
+          },
           {
             "group": "How-To Guides",
             "pages": [