Refactor encounter Actions to use js Classes

[Gazook89]

With #7, each Action will have a few components that are always displayed, but now several more that are only displayed when their Details popup is opened. Since those details disappear when not being viewed, the structure of the Action needs to be changed so that hidden information persists.

I think if an Action can be turned into a javascript Class, it will be easier to assign those properties for each Action.

Also, each Action should be given a unique id# on creation.