This replaces the custom layouts in the navigation drawer with a
`NavigationView` and adds a menu entry for Blogs.
A Main Blogs fragment is added that holds a `TabLayout` and a
`ViewPager`. Five tabs are already added, but they just have a single
placeholder fragment that is to be replaced by the actual fragments.
Closes#409
and indicate which transports are currently available.
The icons have been chosen from the official material icons and might be
replaced later with icons that better represent the given transport.
Please note that I used vector drawables which will be automatically
converted at build time to raster graphics.
Closes#96
