component/slapos: fix compilation by adding missing eggs version

also make sure component/slapos/buildout.cfg is installable in Theia:
 * we can't compile old gobject-introspection with Python3.9
 * we can't patch dbus as it is read only
11 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed Cloudooo.UnitTest-Master

00:06:41

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

00:26:35

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

06:59:02

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

00:28:28

passed SlapOS.Eggs.UnitTest-Master.Python2

00:15:19

passed SlapOS.Eggs.UnitTest-Master.Python3

00:15:05

passed SlapOS.KVM.ResilienceTest-Master

00:20:45

canceled SlapOS.SoftwareReleases.IntegrationTest-Master

00:48:56

failed SlapOS.Theia.ResilienceTest-Master

09:11:55

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:23:15

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

12:49:12