It should be possible to open .duckdb and .sqlite files from the explorer

[softwarenerd]

Clicking on a .duckdb or .sqlite file in the Explorer doesn't open it:

We should do something to make opening these database files possible.

[cindyytong]

https://gist.github.com/softwarenerd/9513342181fa6413773d41e40cd57b2c

@softwarenerd thoughts on this user journey:

1. User opens .sqlite/ .duckdb file inside of Positron
2. Editor pane shows a message with a button depending on whether there is an active connection
3. If there is already an active data connection with the existing file, show
   Button "Explore connection" => opens up the Connection Pane with the data connection selected

4. If there is no active data connection associated with the existing file, show
   Button" Connect to Data" => Opens up the Connection Pane with Add Data Connection selected

Stretch goal: based on the file, pre-populate information about the connection