MongoDB Atlas connection setup has changed since the doc was written

[markwilcox]

In the document here: https://docs.webiny.com/docs/guides/mongodb-atlas
When setting up the connection it only asks to replace the password in the connection string, but following the tutorial in the current MongoDB Atlas console gives this instead:

Replace with the password for the user. Replace with the name of the database that connections will use by default. Ensure any option params are URL encoded.

I don't think the database name matters, but this might throw some people off.

[michizhou]

@markwilcox I have just created a PR that will resolve this issue with updates to the relevant documentation. Please let me know if any additional information or changes need to be made. Thank you.