Allow docker in test actions to add capabilities

Unless the container is started with an extra capability, the test
shell cant mount block devices. Allow the job definition to specify
capabilities that are added to the docker command line.

Change-Id: I41a7e94956629e20d9134b103c71ad98180f5f1a
16 jobs for docker-k64f in 16 minutes and 2 seconds (queued for 4 seconds)
latest
Status Name Job ID Coverage
  Test
passed dispatcher-debian-10 #117718
amd64

00:02:22

passed dispatcher-debian-11 #117720
amd64

00:03:08

passed server-debian-10 #117719
amd64

00:03:06

passed server-debian-11 #117721
amd64

00:05:24

 
  Analyze
passed bandit-sast #117722
amd64-dind

00:00:54

passed black #117723
amd64

00:00:35

passed code_quality #117724
amd64

00:00:20

passed codespell #117729
amd64

00:00:18

passed coverage #117725
amd64

00:06:28

60.87%
passed dockerfiles #117726
amd64

00:00:15

passed pylint #117728
amd64

00:03:04

passed schemas #117727
amd64

00:00:30

 
  Build
passed debian/10 #117731
amd64

00:01:23

passed doc #117730
amd64

00:00:38

passed docker-amd64-dispatcher #117732
amd64-dind

00:03:37

passed docker-amd64-server #117733
amd64-dind

00:04:06