Add possibility to view indices, foreign keys etc.

[ghost]

Is your feature request related to a problem? Please describe.
There is a way to view table description ("Describe table"), but it doesn't show indices and foreign keys.

Describe the solution you'd like
There should be a possibility to view what indices are defined and what foreign keys.

Additional context
Currently, I need to use another application to view indices and foreign keys. It would be nice to be able to use vscode-sqltools to view those.