Add a certificate light for 2G

[rhunger]

Certificate light is currently not supported for 2G. In a 2G situation the certificate full needs to be shown. This violates the original purpose of having a certificate light.

The certificate full reveals too much information. The details of the certificate full is not needed to check 2G.

Implementation hint: It might be necessary to implement a second version of a certificate light to not impair the original certificate light.