Draft: plainui: burning down Bootstrap

• move styles to styles.old for easy c&p while rebuild. Needs to removed bevore merged.
• style.css as new style entry point
• moved loading of context styles files to body class "context-X"
• emptied all class entries via search class=".+?" and replace class=""
• not in body, leaving some of the rc3-bg due to "its complicated" :)

ToDos:

• rebuild basic thme
  • include fonts again
  • basic color and color theming
  • rebuilding style for all templates
• remove old style & unneeded static files (styles.old folder, old grafics etc)
• somebody with npm etc knowledge should check because buildpipeline etc...