New: py-http_ece

Hi ports,

Attached is a proposed port of py-http_ece, a simple implementation of
Encrypted Content-Encoding for HTTP (RFC 8188). This is a dependency
needed for a new port of Mastodon.py.

There are no tests included, but the regression test structure is not
empty. Per off-list discussion with bcallah@ and danj@, I've nonetheless
set NO_TEST=Yes, as running 'make test' with python2 downloads a flake8
package through pip.

Thanks,

Pamela Mosiejczuk