XWIKI-10695: colibri/ie-all.css is applied for Flamingo

- Added an empty .css file that will contain IE related hacks
XWIKI-10695: colibri/ie-all.css is applied for Flamingo

- Apparently if the file is empty it fallbacks on the old Colibri rules. Clearing the browserÕs cache is not working, thatÕs why I added a generic rule in order to reset the file.
XWIKI-10707: Provide a ColorTheme designed for Flamingo Skin

- mark FlamingoDefaultTheme as hidden
XWIKI-10701: Issue with text label alignment in User Profile
XWIKI-10681: Boxes from "Header" section are larger than the panel margins
XWIKI-10774: The LESS compiler always use skins & color themes of the main wiki.