Information about non-compatibility with OSS versions

[n4nn31355]

Readme and description at the marketplace should contain a distinct message that this module doesn't work in OSS versions including link on FAQ.

It sad, that this functional is not available in OSS versions, but even worse, that it's not obvious and information about this situation not lie on surface.

There is plenty of issues:
#1925
#1858
#103
#967
#1767
etc.

[bhack]

More general check also:
microsoft/vscode#81563
microsoft/vscode#83001