Use a single source for map marker icons

Problem/Motivation

When the default map marker icon needs to be changed, it is difficult for site builders to find all the places where the icon is configured (independently):

• OC Map settings
• Location node resp. address paragraph map display
• Views with map attachment

Resolution

Define a single place to change the icon and use the newly configured one (uploaded or by path) in all places.

Notes

The upcoming new theme will include a black icon svg, making it easier to use a colorizing CSS mask. Instructions will be given in via CSS injector. When using both custom icon and CSS mask, make sure the custom icon including the correct path is used as the mask image, too.