Reformat source code using briar's code style

app/src/main/AndroidManifest.xml

...c/main/java/org/briarproject/hotspot/HotspotFragment.java

...ain/java/org/briarproject/hotspot/InterfacesFragment.java

app/src/main/java/org/briarproject/hotspot/MainActivity.java

...src/main/java/org/briarproject/hotspot/MainViewModel.java

app/src/main/java/org/briarproject/hotspot/NetworkUtils.java

app/src/main/java/org/briarproject/hotspot/QrCodeUtils.java

...rc/main/java/org/briarproject/hotspot/ServerFragment.java

app/src/main/java/org/briarproject/hotspot/StringUtils.java

app/src/main/java/org/briarproject/hotspot/WebServer.java

app/src/main/res/layout/activity_main.xml

app/src/main/res/layout/fragment_hotspot.xml

app/src/main/res/layout/fragment_server.xml

app/src/main/res/menu/main.xml

app/src/main/res/values/ic_launcher_background.xml

app/src/main/res/values/strings.xml