Refactor pickers

[irisli]

This PR is a refactor of the Pickers driven by data and the PickerGenerator. This replaces it with a more code-based approach to it.

This also makes pages in the Laboratory persistent between app page change. #44

[nullstyle]

If this action is becoming single-valued, you should reflect it in the name as well: UPDATE_VALUE

[irisli]

Thanks. I should've been using "values" instead of "value" in the first place.

[nullstyle]

You've copy-pasted the same markup for a "text box with validation" too many times for me to endorse this change.

Instead, I think you should add TextPicker which all of these classes (PubKeyPicker, SecretKeyPicker, PositiveIntPicker, AmountPicker, etc.) use instead of repeating code. Their only differences are the "what validator to use" and "what placeholder to use", as far as I can see. So, for example:

export default function SecretKeyPicker(props) {
  return <TextPicker 
    {...props} 
    placeholder={'Example: SAEXAMPLE6TLGEF6ASOTVTLFUK7LE2K2PFVPFGTEZMMVHH7KLLBBROEQ'}
    validator={validator}
    />
}

[nullstyle]

Other than the copy-pasta, +1

[irisli]

Thanks for the useful feedback!