Challenge saving update

Couldn't found a better name for this update but oh well...

Addition/Changes:

• Added/Changed some test questions
• Added a new achievement (be an absolute failure of a student)
• Changed every door color to match the OG animation (classroom's door are green, the rest are red)
• The game now forces an unanswerable question on the first question of a subject
• Updated the keybind menu to actually show the current keybinds
• Custom mode now shows if you have beaten a challenge

Thavel changes:

• Charge speed reduced
• Reimplemented an unused ambush mechanic
• Nerfed Thavel's sneaky attack damage
• Thavel now laugh when she's behind the player
• Thavel speed scale with difficulty now
• Thavel charge the player for less longer

Bugfix:

• Doors no longer randomly open and closes (Blame Thavel for that)
• Fixed the notebook softlock (for real this time)
• Fixed two of HER spawning in the secret gamemode
• Fixed dropout challenge not having teachers
• Fixed challenge having the wrong teachers