Transform CommandAction to type and extend specific enums

[abelzis]

Currently, the CommandAction is an enum, which is too generic and it holds all CommandAction values. My proposal is to add specific enums for each module: enum FieldsCommandAction, enum QueryCommandAction etc. This will provide more clarity from where the actions are raised. If the action is raised from Fields, then the enum should be Fields.

So with this ticket introduce the domain specific enums and refactor the CommandAction to this:
export type CommandAction = QueryCommandAction | FieldsCommandAction | IndexesCommandAction; etc.

@PauliusKu

[abelzis]

Solve in #550