KAN 75 fix(database): fix db persistence timeout and connection lost errors

[FlyingPufferFish]

Testing this PR

Testing large input file:

• run frontend and backend
• upload file of 11k students
• go through timetable generation process
• verify that an output is displayed within 10 seconds

Testing timefold solving timeout limit:

• set quarkus.timefold.solver.termination.spent-limit=60s in application.properties
• run frontend and backend
• upload any test input file
• verify that no errors are thrown and successfully generates timetable after the 60s

Commits Overview

Commit 1: extend db transaction timeout limit to 320s

• This prevents server timeout if we choose to let the TimeFold algorithm run for longer than 60s, because timeout limit defaults to 60s

Commit 2: add logging metrics and enable logfiles

• logged info will appear in the backend terminal once Quarkus app is running
• The same info will be logged to a .log file inside a folder named logs, which lives inside the backend directory

Commit 3: remove storage of students in Unit class to speed up database Timetable object persistence

• The storage of students is the most resource-intensive operation, which caused lost-connection errors when persisting because it was taking so long
• Our current codebase does not retrieve the Student objects after timetables are generated, therefore, they are no longer stored in the database