standalone-shared: more python 3 fixes (execfile)

These crontabs were using execfile which has been removed on python 3.

Switch to `slapos console script.py` syntax which was introduced in
slapos 1.4.5
21 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

15:03:48

failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

31:07:43

failed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:15

failed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

29:50:51

failed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:30

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

15:03:33

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:03:42

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

29:59:19

canceled ERP5.StandaloneDeploymentScriptTest-Debian.Buster

09:13:22

failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

15:09:28

canceled ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

09:13:16

failed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:16

canceled ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

09:11:52

failed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

15:04:06

failed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:00

failed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:28

canceled Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

09:13:47

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

15:04:02

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:04:13

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:03:19

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

15:03:42