Fix docker image build warnings

[BrianSipos]

There are several warnings on recent docker similar to:

WARN: ConsistentInstructionCasing: Command 'env' should match the case of the command majority (uppercase)

There are also two cases of:

WARN: LegacyKeyValueFormat: "ENV key=value" should be used instead of legacy "ENV key value" format

These should be fixed by simply making the case consistent within all Dockerfiles.