Move HTTP message transformation to HTTPtables

[krizhanovsky]

Motivation

With WAF acceleration scenario we need a mechanism to define multi-layer rules, just like we integrate with the Netfilter, but now we need to integrate filters between different cluster nodes - Tempesta FW and a heavyweight WAF.

Use case: run a regular expression over a particular header(s) and set a custom header with a match identifier, e.g. X-Waf-Accel: 10. A WAF receiving the header can perform only checks requiring the pattern or skip checks since they definitely fail.

Scope

Need to support HTTP message modifications as an Action for HTTP tables.

With other HTTP tables extensions like #856 or #1416 , probably it's time to move HTTPtables to some more generic and faster mechanism like BFP. This is essentially #102.

Depends

Requires regular expressions #496

Testing

An extension for existing HTTPtables functional test is required.

Documentation

Update https://github.com/tempesta-tech/tempesta/wiki/HTTP-tables