Suggestions for hints

[Fil]

After PostgreSQL or MySQL Database URL (including username and password) one could benefit from a hint such as
(e.g. mysql:https://dbuser:[email protected]/dbname)

At the end of the registration of a database:
configuration saved in ~/.observablehq
(this could be after each update to the configuration)

launch the proxy with "observable-database-proxy start database"
(this could be a prompt "do you want to launch…")

[maliky]

Should something be said about checking which ports should be open ?