Fixes #12063: Enable "Open with Code" on drives but not recycle bin

Fixes #11244
Fixes #11908

Fixes #11049
See also sourcelair/xterm.js#271

Fixes #12063.
This is a complement to #11870.
Removed the "Folder" registry keys, restored the "directory" ones and added the "Drive" ones.

Part of #11825

This reverts commit 3f0410ad.

Consistently prefix private members with _ to be consistent with ext code and
prevent possible errors with not using correct event handler member.

Part of #10925

Fixes #10925

Fixes #11930