Changed user location dot color to #3070B3

[Marius1501]

I changed the color of the user location dot to a TUM-color (#3070B3). The corresponding issue is #119.

[octycs]

Thanks for your PR! I hope I don't scare you away with these comments at once: You can merge the two definitions into one by using a comma. I think it's better this way. It would also be also possible to write:

.mapboxgl-user-location-dot {
    background-color: #3070B3;
    &::before {
        background-color: #3070B3;
    }
}

(it's one of the cool features of Sass, but because it''s the same color I think it's better to use the comma version I think)

For variables that change with the theme we have the colors all defined in webclient/src/variables.scss. But the map doesn't change with the theme at the moment, so in my opinion it's not necessary to create a variable there.

[octycs]

Nice 👍 I've just seen that there are now two blank lines above and below the background-color: #3070B3; 😅

[Marius1501]

Oh, should I delete them? 😄

[octycs]

Yes, would be great. We usually format them like

selector {  // No space here
    prop: value;
    another-prop: value;
                                    // maybe a space here for readability
    final-prop: value;
}  // No space here

[Marius1501]

Thank you! That`s my first merge! 😄