virt: Separate aexpect spawn kill method

Signed-off-by: Chris Evich <cevich@redhat.com>
virt-sandbox: Implement sandbox virt-test sub-test

Signed-off-by: Chris Evich <cevich@redhat.com>
virt-sandbox: Implement date test

Signed-off-by: Chris Evich <cevich@redhat.com>
virt-sandbox: Implement review suggestions

Signed-off-by: Chris Evich <cevich@redhat.com>
virt-sandbox: Implement sandbox-service

The sandbox service class reuses many of the sandbox-command based
classes along with a service manager.  Like it's relatives, it is
fully pickleable so instances can span across tests.

Signed-off-by: Chris Evich <cevich@redhat.com>