Introducing Endless mode

Hello Cashiers,

You asked, we listened: Endless Mode is here! Customize your ideal shift and play as long as you want. No timer, no stress, no problem.

[h3]Changes[/h3]

• Added Endless mode.
  
• Consolidate score guide into "How to Play".
  

[h3]Fixes[/h3]

• Break room typo.