android: Change how features of VPN types are stored and checked
android: Add EAP-TLS VPN type to the GUI
android: Enable EAP-TLS plugin in the app
android: Handle EAP-TLS in Android service
android: Allow enumeration of untrusted certificates
android: Add support for signature schemes used by EAP-TLS
android: Use %any as AAA identity, but disable EAP-only authentication

Without verification of the identity we can't prevent a malicious user
with a valid certificate from impersonating the AAA server and thus the
VPN gateway.  So unless we make the AAA identity configurable we have to
prevent EAP-only authentication.
Merge branch 'android-eap-tls'

This adds support for EAP-TLS authentication on Android.

EAP-only authentication is currently not allowed because the AAA identity
is not configurable, so to prevent anyone with a valid certificate from
impersonating the AAA server and thus the gateway, we authenticate the
gateway (like we do with other authentication methods).
Also, it's currently not possible to select a specific CA certificate to
authenticate the AAA server certificate, so it either must be issued by the
same CA as that of the gateway or automatic CA certificate selection must
be used.
android: Enable IKEv2 fragmentation
android: Increase fragment size

We use the same value we use as MTU on TUN devices.
android: Build binaries for MIPS
android: New release based on 5.2.1 and after adding EAP-TLS

Also enables support for IKEv2 fragmentation, provides improved MOBIKE
handling and optionally enables PFS for CHILD_SAs.