Use double quotes for parameters - reapplies the 3 commits recently reverted

This fixed the recent login failure. It failed because the password param was in single quotes. This changes it so that when the password is provided as an environment variable it's expanded to the variable value instead of being passed as the environment variable a literal string value.

This also reapplies the three commits that were reverted when docker login was failing, so squash and merge isn't enabled.

• When this is merged, announce to the team that docker images will be pulled by default. QA_SKIP_PULL=true can be used to skip pulling images if they already exist.