Unfortunately, if a doc finishes decryption before the previous one we
will still have an issue while inserting. This commits solves it by
adding the parse and decrypt inside of the semaphore.

Document sending happens after encryption, so the last sent document
needs to be signalled after request end.

Fixes setup.cfg, adding current exclude rules, simplified tox.ini to use
setup.cfg and fixed all.

Also refactored tests and code to stop relying on old parameters which
included docs instead of get_doc calls.

Deferred encryption option is gone.

We aren't using leap.common.http implementation and we need specific
features from original Twisted Web Agent. This commit implements it on
HTTP Targer.

Parsing from metadata we can store the total of docs and handle it for
the doc parser in order to be able to keep consistent events info.