Check if via searches work

[leonardehrenfried]

In the OTP2 meeting I heard that via search (= searches with an intermediate location) don't work.

Please verify if that is true and investigate how much work it is to add this feature.

[flaktack]

Intermediate locations aren't currently supported in OTP2, there is an issue for it with an initial implementation which would need to be worked on: opentripplanner#3183 (comment)