Remove hardcoded paths

[ktaekwon000]

While implementing some new features that involve storage, we hardcoded the data directory into our application, making our application unable to be configured with a custom file path.

I don't think this is a requirement for the application (I didn't see any relevant constraints on the tP info page) but this goes against the design of the existing ab3 application.

[ktaekwon000]

In the process of coding my own tests, I found that the test code heavily depends on variable file paths, and it would be hard to write test code for the sections with hardcoded paths.

As testability is a grading criterion (I think?), I am increasing the priority of this issue.