Convert breezy CSS to LESS code

Less is a language which can be compiled to css but allow for better syntax and use of variables. The idea is to convert the breezy css files to less files using variables for colors, font and such, allowing to easily create new themes close to breezy but with other colors.

Actual behavior

CSS is used with hardcoded colors and fonts.

Expected behavior

Easily create new themes with other colors and fonts.

Step by step description of new behaviour

1. Convert breezy css to less css
2. Add these less files to the repo
3. Add a compiling option to packaging to generate the css files

Benefits

Easy to customise theme, make sure current theme is consistent.

Possible Drawbacks

New compiling step for CSS