Implement a file-naming convention that is safe

Currently on ehr-utils.js, we have a function called makeSafeFileName which needs to be implemented in a way that doesn't break the build.

Previously (as you can see it commented out currently), we used to implement filenamify to handle this, but this implementation was breaking the build.

With that in mind, the task at hand is to create a new implementation (or re-implement filenamify) in a way that won't break the build. We encorage using conventions that are easy to read and understand at first glance.