Implement support to validateHash operator into libmodsecurity

[zimmerle]

Operator validateHash needs to be implemented inside libmodsecurity.

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

The file already exist in the repository:
https://github.com/SpiderLabs/ModSecurity/blob/libmodsecurity/src/operators/validate_hash.cc

[zimmerle]

The operator @validateHash is something that is part of the hash engine, which demands content injection. Since content injection is not supported in v3, i am marking this feature as deprecated.