MAJOR: filters: Revert the filter-sequence directive

MAJOR: filters: Revert the filter-sequence directive

The filter-sequence directive was introduced to be able to define a
different evaluation order of filters for the request and the response. The
first usage should be to mix the compression and the decompression, when a
specific order must be defined.

However, there were several bugs. And working on fixing those bugs, it
appeared that the feature was underdesigned. To fix the bugs, the syntax of
the directive must be changed. And even this way, it will be difficult to
use it properly.

In fact, we really underestimate the changes to perform. So we decided to
revert the directive for now, especially to remove it from the 3.4. It is
not really mandatory on this version. Because of all current bugs, it was
probably not used yet on production. On 3.5, the feature will be fully and
deeply redesigned because it is mandatory.

This patch reverts the following commits:

  * efe1099c3 ("BUG/MEDIUM: filters: check the filter name before comparing it")
  * 3eebd5f67 ("REGTESTS: add a test for "filter-sequence" directive")
  * 8d28c0e37 ("MEDIUM: filters: add "filter-sequence" directive")

It must be backported t 3.4.