TASK: refactor codebase with MVVM

use MVVM structure

What we will do:

• separate data classes into entities folder
• create model class & interface
• create persistence interface
  • create firestore class that inherits persistence interface
• changed study rooms collection in firestore
  • change building field to not be acronyms (SLC -> Student Life Center)
  • roomNumber stays the same
  • add "name" field to be building acronym + roomNumber (SLC 123)
  • change any instances in the codebase (fullName doesn't need to be created by appending the 2 anymore, can just use the name field)