Allow to select multiple table columns from connections tree and copy them into text editor

[dnlw07]

Is your feature request related to a problem? Please describe.
Currently it is not possible to copy multiple table columns from connection pane. Extension allows only to directly paste into text editor single column by clicking on a particular column.
If you want to paste multiple columns you need to click each column one by one.

Describe the solution you'd like
Allow to select multiple table columns at the connections tree and copy them (using Ctrl+C) into text editor. Column names can be separated by comma (,) or new line (\n).