Improve styleguide

[nicolas-brousse]

• Use ActionController::Base instead ApplicationController for Styleguide
• Set locale in Komponent::StyleguideController
• Remove components helper and move into Komponent::StyleguideController
• Support static pages on Styleguide Add static pages support to Styleguide #114
• Add nested components support in styleguide Add nested components support in styleguide #125
• Add tests

Closes #114, #125

[nicolas-brousse]

Does using markdown file for static pages is a good idea?

Having static pages in frontend/component could be nice. By using markdown the mean we may have something readable directly in Github/GitLab repository or in IDE.

[Spone]

Does using markdown file for static pages is a good idea?

I think we should support any templating language supported by the main application, so you could potentially use erb, slim, haml, ...