STA: Allow PTK rekeying without Ext KeyID to be disabled as a workaround

STA: Allow PTK rekeying without Ext KeyID to be disabled as a workaround

Rekeying a pairwise key using only keyid 0 (PTK0 rekey) has many broken
implementations and should be avoided when using or interacting with
one. The effects can be triggered by either end of the connection and
range from hardly noticeable disconnects over long connection freezes up
to leaking clear text MPDUs.

To allow affected users to mitigate the issues, add a new configuration
option "wpa_deny_ptk0_rekey" to replace all PTK0 rekeys with fast
reconnects.

Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>