create docker tests (end-to-end)

[mki-c2c]

first ideas (this is a very preliminary analysis, it is rather a list of ideas. In the final implementation, there may be some additional parts or some parts may be unnecessary)
should cover:

• end-to-end pdf generation
• verification of contents (varying contents (timestamp, uuid, may be mocked)

potential architecture:

• new github repo with version compatibility information from the different components (oereb_server, MFP, oereblex, etc.)
• some acceptance tests on a complete test enviranment with all components
• possibility to create a common install script to deploy the whole system with options to include or exclude some parts

[vvmruder]

This Issue is related #1436. Important seems the fact to not rely on python necessarily to test. And more important is the testing of JSON/XML then the testing of PDF. The latter can have arbitrary deep difficulties in term of testing.

[vvmruder]

@voisardf @svamaa We need to talk about this => workshop?