Fix: Escape backslashes in component source string

[dennisppk]

When defining components with a source to a (relative) local path in Windows, backslashes should be escaped within the module definition in site.tf for it to work. A single backslash is interpreted as escape character. Windows uses a backslash as path separator.

[demeyerthom]

@dennisppk I have not forgotten about this PR, but I want to update our testing so we also test windows cases first. Ok if I put this on ice until that has progressed a bit more?

[dennisppk]

Yes sure :). In the mean time I can use my own build that contains the fix.