Please check DHE key size in TLS handshake to service provider

[psytester]

To reflect the current working of AusweisApp2 the eIDClientCore needs to check the Diffie-Hellman key size given by eID service provider during TLS handshake.
This happens if eID Client sends a Client-Hello with its cipher suites and the service provider selects a DHE-*** suite.
Since 2016 the AA2 (version 1.6.1) accepts only 2048 bit DHE keys and 1024 or less are rejected.
From test point of view I would like to have an optional parameter to switch off that check.