Proposal: Support Unity Catalog visually #52

Proposal

Some time ago I raised a pull request (#42) to handle catalog selection with visual references, which is a benefit for Unity Catalog. That PR was raised in March so the code has diverged, but more interesting the use command was removed in v0.3.0.

I have been using my version of the dbsqlcli that supports the functionality highlighted below, and recently had a colleague see me using catalogs in a very simple way. He ask why I was able to do this and not himself, so felt compelled to raise this issue.

Enter into a Database under a Catalog using use

dbsqlcli
dbc-12fcx123-12f:hive_metastore.default>
dbc-12fcx123-12f:hive_metastore.default> use dev.analytics;
You are now connected to database "dev.analytics"
Time: 0.616s
dbc-12fcx123-12f:dev.analytics>

Enter directly into a Database under a Catalog

dbsqlcli dev.analytics
dbc-12fcx123-12fc:dev.analytics>