Remove duplicate internal/external location source selection

[dominikargast]

The settings page offers the choice between internal and external position source. When choosing the external option, the device selection page appears, which contains the internal, network, and external device options.

The choice on the settings page is thus redundant and should be removed in favour of the device page, which contains all options in one place.

Settings page:

Devices page:

[dominikargast]

@marikavertzonis test with build 3.1.2

[marikavertzonis]

tested with 3.1.2 built with framework 3.1.110 and see just the connecting / connected device message on the settings page, and built in location choice only on the choose location service page.