LU-17461 dkms: improve /etc/sysconfig/lustre

LU-17461 dkms: improve /etc/sysconfig/lustre

Expand the features available in /etc/sysconfig/lustre
to enable more flexability to dkms users.

Providing y/n switches for common features:
    LUSTRE_DKMS_ENABLE_GSS=y/n
    LUSTRE_DKMS_ENABLE_GSS_KEYRING=y/n
    LUSTRE_DKMS_ENABLE_CRYPTO=y/n
    LUSTRE_DKMS_ENABLE_IOKIT=y/n

As well as a catch-all to pass to configure:
    LUSTRE_DKMS_CONFIGURE_EXTRA='string passed to configure'

Add suport for dpkg checking for libkrb5-dev to enable or
disable gss by default, if it is not otherwise specifed.

HPE-bug-id: LUS-12097
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: Id8dd17c867d9aeb1ec27632729433ba128dcfd0a