text: Title: Move themes out to separate files
  Body: All current themes are defined inside a `theme.py` module. It looks like the next:
  ```
  elif theme == "midnight":
          # {{{ midnight
  
          # Based on XCode's midnight theme
          # Looks best in a console with green text against black background
          palette_dict.update({
              "variables": ("white", "default"),
  
              "var label": ("light blue", "default"),
              "var value": ("white", "default"),
           ...
  ```
  I propose to create a separate folder, for example, `themes`. Each theme will be as a separate file JSON or YAML inside a created folder.
  
  I think the theme is not related to an application. Consider a terminal or popular text editors. All of their themes are separate files which easy to install without changing a code.