software/beremiz-runtime: add md5sum option

Use md5sum to check if what we download is what we actually got.
Status Job ID Name Coverage
  External
passed Cloudooo.UnitTest-Master

00:18:41

failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

15:02:14

failed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

15:02:33

passed SlapOS.Eggs.UnitTest-Master.Python2

00:25:35

passed SlapOS.Eggs.UnitTest-Master.Python3

00:27:03

failed SlapOS.SoftwareReleases.IntegrationTest-Master

11:55:21

passed SlapOS.Theia.ResilienceTest-Master-ERP5

11:10:05

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:44:46