[AdityaHegde]

Adds support for alert and report for embedded users.

Changes needed by user,

1. GetIframe request needs user_email passed to enable alert/report.
2. alert & report feature flags need to be enabled in rill.yaml (These have been changed to {{ not .user.embed }} so that it is opt-in)
3. navigation: true is not mandatory, but with it 2 icons are added top right for going to alerts/reports page and to open the dialog.

4. navigate embed API is added to control the page from outside.
5. Pending, decision on how Open button from email works.

Technical details

1. Added embed_auth_token similar to service token to grant temporary access to cloud. This only has access to manage alert/report.
2. APIs either use cookie or embed_auth_token to make alert/report calls.
3. APIs ensures embed_auth_token can either create or edit/delete own alert/report.

TODO: Figure out how Open from emails work. Open embedder's page with some params? Or is the current implementation enough?

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!