Implement the support to setuid action in modsec v3

[zimmerle]

The support for setuid is not yet implemented.

Further information about it can be found here:
https://github.com/SpiderLabs/ModSecurity/wiki/Reference-Manual#setuid

[zimmerle]

Implemented. d96d54e

[ossie-git]

This never made it into 2.9.1, did it?

[zimmerle]

@ossie-git This is about implementing something that was on 2.9.1 but wasn't on v3.