Set up a STATIC_ROOT directory for tigerapps

This change instructs the `manage.py collectstatic` command to copy static files to a separate `tigerapps_static` directory in the root of the repo. This ensures that Apache can find static files from child apps. Currently, Apache is only serving static files from the `tigerapps/static` folder. This leads to broken references when linking to resources in child apps, such as the `django_tables2` lib used in the wintersession app. The issue does not occur in development due to the built-in server automatically traversing child apps for static files. 

An extra deployment step, running `manage.py collectstatic`, is now needed if any static files have been updated. Apache should also be configured to serve files from the new static files directory.