Android 11 support with Suggestion+add network action

[pauldekkers]

Use Suggestions with ACTION_WIFI_ADD_NETWORKS to add networks properly in a build compatible for Android 11, so the networks end up in the users managed network list.

https://developer.android.com/guide/topics/connectivity/wifi-suggest
https://developer.android.com/reference/android/provider/Settings?hl=en#ACTION_WIFI_ADD_NETWORKS

It should work both with minSdkVersion = 30 and targetSdkVersion = 30 (to upload an Android 11 specific build) as well as the existing settings for a more generic .apk.