[Feature] Integrated Navigation

[CommanderStorm]

Is your feature request related to a problem? Please describe.

This issue is motivated by this state of the art:

Currently, one would need to switch to google maps or apple maps.
Going foreward, NavigaTUM wants to allow indoor navigation.
The TUM campus app is a really good target for this.

In the endgame, I want to be at a state like this, but we are a long way away from this:

Apple	Google

Describe the solution you'd like

I think integrating ferrostar should be fairly™️ straigtforeward, going by:

we have reports from a user in Slack successfully using this with Platform Views (the second approach). So this is not a prod onboarding blocker, but it is still something we'd like to make easier.

• [Flutter] Frontend components stadiamaps/ferrostar#106
• [Flutter] Look into Dart binding generation stadiamaps/ferrostar#16

The valhalla instance is at https://nav.tum.de/valhalla.
It currently does have the following limitations:

• no elevation data
• no gtfs traffic ("ÖPNV") or bikesharing data
• no realtime car traffic data

Describe alternatives you've considered
The obvious alternative would be to see and wait how ferrostar evolves and only integrate this into the Campus App afterwards (and after navigatum has fully figured out all the issues)

Additional context
If somebody would like to investigate this, feel free to reach out and ping me if you run into any issues ^^.

[!WARN]
I have no idea if this a simple/hard issue.