core: remove ConnectionWrapper

Change-Id: I41e385f266837c7b45b0d5d1c02402e8ee9eb155
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>
core: Add ImportCertificateCommand

Change-Id: If4308ecb184234fee3931cf4c7cfbd1796efa9d2
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>