De-Couple EA from EaType

EAs are basically the same regardless of type. (`computer`, `mobile`, `user`) Right now the strategy/facade wants only a single type at a time, and treats them somewhat differently. The framework is there to handle them all as one giant EaList object, as each EA has it's type attached to it. We should beef up the strategies/facades to not particularly care about the type of EA at the beginning, and only when it encounters the individual EA object. This would make it simpler to sync all EAs from disk to Jamf, for example, as a single `EaList` object could be generated and passed to the Jamf strategy.