docs: windmill integration docs

[jakcinmarina]

Windmill integration docs, based on this PR (it can be closed now)
Added:

• new screenshots for verified scripts
• oauth screenshots
• edited the flow instructions as it cannot be forked from hub.

---

Note

Introduces a new integration doc for using Apify with Windmill, including setup, auth, and workflow examples.

• New page sources/platform/integrations/workflows-and-notifications/windmill.md with end-to-end guide
• Covers installing/importing Apify scripts from Windmill Hub and available components (actions, triggers, resources)
• Details authentication options: API key resource, script binding, and Cloud-only OAuth
• Walks through building a sample flow: Run Actor → Get Dataset Items, with test/run steps
• Guides webhook-based triggers setup (example flow import via YAML, webhook config resource, creation/deletion) and mentions polling triggers
• Lists supported operations (Run Actor/Task, Scrape Single URL, Get Dataset Items/Key-Value Store) and references docs/resources

^{Written by Cursor Bugbot for commit 44119dd. Configure here.}

[drobnikj]

Just one note, but pre-approving

[drobnikj]

This should be step 5 or the 2nd titile like ## Deleting the webhook