minor improvements

[bitstarr]

• [x] Add dependency for svg-extension plugin
• [x] add simple shortcodes (e.g. for svg-extension)
  • [x] add "Editor buttons" (plugin dependent, optional)
  • [x] add shortcode default config to kickstart project
  • [x] document available shortcodes
• [x] revisite css reset again (https://piccalil.li/blog/a-modern-css-reset/)
• [x] do something to drop gravatar
• [x] add a source/author field to hero component

[bitstarr]

• gravatar is system bound, but it went into my project kickstarter
• Editor buttons don't need a plugin, they're simply assets 🎉