Specifically, if they set a 'notes' property on their metadata object,
it will be displayed in the console version of their results, for
easier debugging.
The health check ensures that s3, aestimia, openbadger, and MySQL
connections are all functional.
Currently the cookie secret is used as the password at /health_check but
we can change this later in app.js.
I also added some code that checks to see if the required CSOL_AWS_*
env vars are defined; if they're not, it throws a helpful error and
mentions that CSOL_AWS_FAKE_S3_DIR can be used as an alternative.
Unfortunately I haven't been able to test out this integration yet,
because I'm having trouble figuring out how to upload evidence locally on
the website...