Add style for skipped jobs
Add style for skipped jobs

By default is used white font on white background. Add class 'label-info'
for skipped jobs.

Change-Id: I33afaca27d202631271b6244116f0df36670a4ac

wikimedia/integration-zuul,wikimedia/integration-zuul,gooddata/zuul,gooddata/zuul,gooddata/zuul,wikimedia/integration-zuul,gooddata/zuul,wikimedia/integration-zuul,gooddata/zuul