Inputs - Extract all the methods from actions in services, add docs, refactor methods

[DariusMuscalu]

1. We need to extract all the methods (which provide document operations logic) from actions and move them into specific services. (e.g. A method that affects styling should be moved to styling service.
2. Also, we need to proper document everything, refactor methods name to be accordingly to the service name (e.g. each method that is affecting styling of the document almost all the time is in correlation with the selection so it should include 'selected' or something similar into it's name.).
3. Check for code that is using methods from the state inside actions. We should always use the code from the services.
4. Add documentation for Inputs inside inputs.md explaining how it works, also check if we already have actions.md, if not create it and add docs.

This is the improvement for the previous ticket: https://github.com/visual-space/visual-editor/issues/163