[Docs]: Replace Appsmith DB url from APPSMITH_MONGODB_URI to APPSMITH_DB_URL in env references

[abhvsn]

Problem Statement

We are in a transition to move DB from MongoDB to Postgres that Appsmith uses to persist the data for all entities like users, workspaces, applications, datasources etc. We are making sure we have a fallback for our existing users to support the backward compatibility, but for any new installation we want to start consuming the updated env variable.

Use Cases / User query reference

As of today we refer the DB url with env APPSMITH_MONGODB_URI which needs to be updated to APPSMITH_DB_URL.

Audio/Video Recording

No response

Product Requirements Document

No response

Other Relevant Links

https://www.notion.so/appsmith/Move-to-Postgres-110125e2c94145848b67abd40b7a4a8c

Checklist

• Reviewed existing documentation to ensure this request is not duplicated.
• Attached relevant media or supporting materials like links to the PRD, feature recordings, Slack or Discord links, and any other relevant resources.