Add method for passing environment variables to accumulo-env.sh

[t92549]

Currently, one environment variable is explicitly added to the accumulo-env.sh from the tserver/statefulset.yaml: https://github.com/gchq/gaffer-docker/blob/266e45106fb2b9f0452bf30fff05fba0a2c06c6d/kubernetes/accumulo/templates/tserver/statefulset.yaml#L37-L46

However, that file uses lots of environment variables to set a lot of things: https://github.com/gchq/gaffer-docker/blob/266e45106fb2b9f0452bf30fff05fba0a2c06c6d/kubernetes/accumulo/config/accumulo-env.sh#L34-L41

Therefore, it would be good if the tserver/statefulset.yaml had an option to take an abitrary number of environment variables from the values.yaml and set them.