[WIP] add webtests, first try frontend test

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | no
| Fixed tickets | https://github.com/symfony-cmf/RoutingBundle/issues/230, parts of https://github.com/symfony-cmf/symfony-cmf-docs/issues/444
| License       | MIT
| Doc PR        | need to be created

Please do not be confused, but i try to understand that Prefix/Candidates thing. To do that i (re-)activated the frontend test, do not no why they where not active. Then i created some routes, i just wanna play how `idPrefix`, `staticPrefix`and the candidates work together.

I got an issue with instantiating the database for the test - hope not to have it in travis.