devel/venom: new port

Venom allows you to handle integration tests the same way you code your
application. With Venom, testcases will be managed as code: the readability of
the tests means that the tests are part of the code reviews. Thanks to that,
write and execute testsuites become easier for developers and teams.

Concretely, you have to write testsuite in a YAML file. Venom run executors
(scripts, HTTP Request, web, IMAP, etc.) and apply assertions. It can also
generate xUnit result files