[STAR-2547] - Add iPython for better REPL.
This MR adds iPython to the requirements list. Django picks this up and will use it for its management shell.
JIRA tickets: https://tasks.opencraft.com/browse/STAR-2547
Testing instructions:
- Build the image or else install the requirements if using an existing install.
- Run
make shell
- Run
./manage.py shell
- Verify the shell is colorful and says it is iPython.