Flexbox layout for cgi, css now lives in separate file.

###### What have been done:
- HTML layout of generated CGI has been reworked for better look when there are lots of separate root paths in database.
- Also I've separated css from cgi to be able to work in more flexible way with styling, if it will be required in a future.

###### Still needs to be done:
- I have no idea how this ugly configure/makefile system works and how to add css/duc.css file into 'make install' pipeline,
for it to be installed in /var/www/css/duc.css or other prefix if static server is not apache.