containers: Add chromium to unit-tests container
containers: Add chromium to unit-tests container

In PR #8314 we will port the unit tests from PhantomJS to Chromium.

Closes #8349

SotolitoLabs/cockpit,mareklibra/cockpit,garrett/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,andreasn/cockpit,cockpit-project/cockpit,petervo/cockpit,andreasn/cockpit,martinpitt/cockpit,deryni/cockpit,mareklibra/cockpit,stefwalter/cockpit,cockpit-project/cockpit,martinpitt/cockpit,stefwalter/cockpit,cockpit-project/cockpit,andreasn/cockpit,martinpitt/cockpit,stefwalter/cockpit,Scribery/cockpit,petervo/cockpit,cockpituous/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,stefwalter/cockpit,stefwalter/cockpit,cockpit-project/cockpit,SotolitoLabs/cockpit,garrett/cockpit,SotolitoLabs/cockpit,Scribery/cockpit,mvollmer/cockpit,Scribery/cockpit,deryni/cockpit,mvollmer/cockpit,mvollmer/cockpit,Scribery/cockpit,SotolitoLabs/cockpit,petervo/cockpit,petervo/cockpit,deryni/cockpit,martinpitt/cockpit,deryni/cockpit,andreasn/cockpit,garrett/cockpit,petervo/cockpit,Scribery/cockpit,petervo/cockpit,cockpit-project/cockpit,cockpituous/cockpit,Scribery/cockpit,andreasn/cockpit,deryni/cockpit,deryni/cockpit,cockpituous/cockpit,SotolitoLabs/cockpit,mvollmer/cockpit,garrett/cockpit,andreasn/cockpit,mareklibra/cockpit,cockpituous/cockpit,garrett/cockpit,martinpitt/cockpit,mareklibra/cockpit,mareklibra/cockpit,petervo/cockpit,Scribery/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,andreasn/cockpit,moraleslazaro/cockpit,mareklibra/cockpit,deryni/cockpit,mareklibra/cockpit,cockpituous/cockpit