Multi line variables supporting

[dennypenta]

The issue:
vscode itself doesn't support multi line env variables, it's useful to support json values in variables, (ref: microsoft/vscode-python#9251)

Solution:
add a flag that will allow to reformat multi line variables, remove all the spaces (also \n, \t) and override a value in one-line.

[dennypenta]

I implemented this piece.
https://github.com/dennypenta/vscode-env-formatter
If anyone interested - just add some tests and integrate it