change how jmdns is integrated

[bk138]

Right now, we have jmdns running in a background service in order to have mdns discovery decoupled from the mainacitvitiies on-rotate re-create(). Starting from android Oreo, this should probably be a ForegroundService (with an ugly notification) or something else...

https://stackoverflow.com/questions/46445265/android-8-0-java-lang-illegalstateexception-not-allowed-to-start-service-inten

[bk138]

https://developer.android.com/about/versions/oreo/background.html

[bk138]

https://stackoverflow.com/questions/52398630/illegalstateexception-in-oncreate-application-class

[bk138]

Not fixed. Maybe steal from https://github.com/mapbox/mapbox-events-android/pull/157/files

[bk138]

https://issuetracker.google.com/issues/117790600