Implement the support to t:removeWhitespace into libmodsecurity

[zimmerle]

Transformation removeWhitespace needs to be implemented inside libmodsecurity.

The documentation of the transformation can be found here:
https://github.com/SpiderLabs/ModSecurity/wiki/Reference-Manual#removeWhitespace

The file already exist in the repository:
https://github.com/SpiderLabs/ModSecurity/blob/libmodsecurity/src/actions/transformations/remove_whitespace.cc

[zimmerle]

Pull request #1115.