Use all SIM cards available

[mic-max]

• If the phone has more than 1 SIM card, show that in the GUI
• Allow it to be a proxy for a different HTTP endpoint

[mic-max]

• https://stackoverflow.com/questions/11305407/android-dual-sim-card-api
• https://developer.android.com/reference/android/telephony/SubscriptionManager.html#getActiveSubscriptionInfoList%28%29