Map updates.

Add support for different map types (street/satellite) and different map
providers.
Support finding real world addresses on the map.
Add Maidenhead locator converter.
Add Beacons.
Allow data sources to be selected by a user.
Add context menu to allow setting an object as a target, setting center
frequency and adjusting display order.

plugins/feature/gs232controller/gs232controllersettings.cpp

@@ -25,11 +25,13 @@
 
 const QStringList GS232ControllerSettings::m_pipeTypes = {
     QStringLiteral("ADSBDemod"),
+    QStringLiteral("Map"),
     QStringLiteral("StarTracker")
 };
 
 const QStringList GS232ControllerSettings::m_pipeURIs = {
     QStringLiteral("sdrangel.channel.adsbdemod"),
+    QStringLiteral("sdrangel.feature.map"),
     QStringLiteral("sdrangel.feature.startracker")
 };