* use generic advective flow method

* similiar to PM flow, takes lambda to get transported quantity

* use tag dispatching for different discretizations

* clean up

* do some clean-up as well

Feature/test angeli

See merge request !653

* Adapt fluidsystem
* make some variables const

Cleanup/remove default components prop

See merge request !658

Improve properties

See merge request !630

* do not inherit from ModelProperties
* use CMAKE_GUARD to skip test if alugrid not found

* add new test, only checking a simple scvf
* improve free-flow specific test