Feature: Make Waypoints in RoutingView draggable

[kruegercharles]

See: https://trello.com/c/2hRM1W4v

• Figure out how is the waypoint currently placed on map
• Implement test if user clicked on an existing waypoint ⟹ use distance on screen not distance via GPS
• Use correct icons for dragging waypoint or destination
• Use animated container during drag (used animatedpositioned)
• Fix: the destination of the route must always stay the same, except when the user drags the destination
• Feedback Daniel: use onMapTap to check if user tapped on waypoint (we get features with screencoordiantes....maybe we need to name the waypoints) (discarded because my implementation works fine - no need to change)
• Make waypoints draggable
• If dragging waypoint the map should not move and vice versa
• Old waypoint must be removed from history & new waypoint must be added to history after dragging
• Waypoint has to be updated in BottomSheet after dragging
• Route must be updated after dragging
• Add short animation: Start dragging makes icon bigger and stop dragging makes icon smaller (discarded because it didn't work well)
• When dragging to the edge of the screen, move the screen
• Fix: Why does it shortly show the waypoint icon when releasing the destination icon??
• Try: use tapping detector instead of longPress detector to "fake" a longPress detector with shorter delay (discarded because it didn't change anything. I still had to press for approx. 1 second on waypoint to select it)
• Fix: When dragging waypoint to screen edge it movement eventually stopps - is this fixable or a problem of onLongPressMoveUpdate? (with onLongPress I don't have details provided to get the tapped position of user)
• Refactore Code from Daniel
• Fix: When a waypoint is dragged outside of the city boundries, it is deleted ⟹ it should be restored at old position
• Fix: The new position after dragging is often very inaccurate
• Test on different device sizes: check map move speed and ability to drag waypoint
• Test on IOS
• Rewrite Android-Code by also moving with coords instead of moveTo? (thats not a good idea because using gps means mapmovement gets faster when zoomed in)
• Add delay (maybe 10ms) to camera-movement to slow down and use slower speed?
• Circles around waypoint when dragging
• button to cancel dragging

[PaulPickhardt]

As discussed f2f:
Maybe we can try to add auxiliary markers around the dragged waypoint to help the user to place the marker and to even recognize that the marker is draggable.

Also we should implement a cancel bin to enable aborting drags.

I started the auxiliary marking animation. Please have a look @kruegercharles. Maybe there is a way to let a container grow from the center. Otherwise we need to define an animation that also effects the Positioned widget.

[kruegercharles]

As discussed f2f: Maybe we can try to add auxiliary markers around the dragged waypoint to help the user to place the marker and to even recognize that the marker is draggable.

Also we should implement a cancel bin to enable aborting drags.

I started the auxiliary marking animation. Please have a look @kruegercharles. Maybe there is a way to let a container grow from the center. Otherwise we need to define an animation that also effects the Positioned widget.

I've fixed the position of the cancel button. It now works on the small Nexus, the bigger Motorola as well as my phone. Please test if it works on iOS too.
Other than that I think this PR is done 🙂

[PaulPickhardt]

Great work @kruegercharles!

Feature looks really cool.

Just did some minor refactoring.