Show input/output icons of storages when planning routes

Currently If you plan routes you can't properly see what is exporting or importing what.
It would be good to see all storage connector types as in building mode.

See the image.
You try to export rock to other storages but you can't see what is configured to rock.

During route selection:

Solution 1 (ok)
- always show all connectors of storages of the same type (flat or u-shaped).

Solution 2 (better)
- if your storage is not configured for any resource - show only compatible connectors for storages of the same type (flat or u-shaped)
- if your storage is configured for particular resource - show only compatible connectors of storages that have the same resource type

Both of these solutions make selecting routes easier and more intuitive.
If I export rock, I will see which storage is configured for rock.