Possibility to upload onlinemaps.xml and wms_services.xml for automatic install

[bens]

On recent versions of Android, the transfer of our personnal "onlinemaps.xml" and "wms_services.xml" in the good directory can be very tricky.

It is often a big problem for new users that lead them to give up oruxmaps.

On AlpineQuest and Locus, the configuration files of map layers can be very easily installed by just "open with" the app => the file is copied to the good directory without the hassle of manualy finding it or be blocked by the security functions of Android.

It could be also an item in the app menu like "load map settings file"