Pass Java arguments to Docker containers

Description

Updates the Dockerfiles so end-users can pass arbitrary Java arguments.

Changes

• Updated documentation

Additions

• A JAVA_ARGS env-var containing arbitrary arguments

Test and Review

To be filled in by the reviewers

• All of the methods are commented to expectation

• The methods are tested to satisfaction

• There are no unnecessary files present in the MR

• The continuous integration has no problems with the MR

• The MR is filled in as requested (including labels, milestones, and reviewers)

• The documentation is up-to-date

• All nullable parameters are marked as such