Makes the client's IKE identity configurable in the NM GUI. For PSK
authentication the identity is now configured via that new field
and not the username anymore (old configs still work and are migrated
when edited). The client identity now also defaults to the IP address
if not configured when using EAP/PSK.
+ <property name="tooltip_text" translatable="yes">Defaults to the username (EAP), the client certificate's subject DN (certificate/EAP-TLS), or the IP address (PSK). Custom values may be used if expected/required by the server.</property>