Prepared states

[zatziky]

@karelrochelt had an interesting idea that states are repeated over and over and only some states really deserve to have the comfort of a custom state in a separate file.

For example, a lot of states just send a text. We could create a TextState:

new TextStateBuilder()
  .addText('some text')
  .addNextState(anotherState, () => true)
  .build()

A lot of other types can be added too. How will we implement this?