Initialization of Utility Class

- Created the utility class to perform
  the convert() and revert() function
  of the field class to conform to
  the single responsibility principle
Update to KeyStorage

- Realized that KeyStorage obviously needs to be
  utilizing a linked list for Nodes.
- The linked list is currently a nested class in
  keyStorage but we might want to create a separate
  class for it to reuse it elsewhere.