Replace field alias concept with simpler system

Created by: dbluhm

Aliases were introduced to address the problem presented by privateId's getter being getUUID() instead of getPrivateId(). The concept of Aliases was needlessly complicated to solve this problem and otherwise unused anywhere else in the project. In it's place, varName was introduced on Field that can hold the variable's name when it differs from the name of the field itself, i.e. in the privateId scenario, the varName is privateId and the field name is UUID.