Issue 307 - Adding xms and xmx for Cantaloupe heap

[g7morris]

Per #307

[noahwsmith]

I've tested this in our base project, the variables do what we want and things work pretty well. I snuck in adding a missing library libjpeg-turbo.

[g7morris]

@noahwsmith Awesome! Do note, this change will require downstream isle-dc users to add these two new variables, Im guessing either in the docker-compose.yml file or the .env file. I'll work on crafting a PR to that effect once these changes are approved and merged.

[noahwsmith]

You've set default values so it technically doesn't require a change, but folks should know that the defaults have been set and how to change them, for sure.

[aOelschlager]

Tested this in isle-dc. I pulled in the 307-set-heap-sizes-for-java-in-cantaloupe images and ran ps aux | grep java in the cantaloupe container which displayed the default values for xms and xmx. I then used the xms and xmx variables in my docker compose file but set the values a different amount than the default values. I restarted the containers and I ran the same command as before and it displayed the values from my docker compose file.