Remove font definitions and references from output

[kayhayen]

Currently, the CSS contains these font-face declartions that must not reference URLs for their sources.

@font-face {
	font-family: Lato;
	src: url(fonts/lato-normal.woff2?bd03a2cc277bbbc338d464e679fe9942)
			format("woff2"),
		url(fonts/lato-normal.woff?27bd77b9162d388cb8d4c4217c7c5e2a) format("woff");
	font-weight: 400;
	font-style: normal;
	font-display: block;
}
@font-face {
	font-family: Lato;
	src: url(fonts/lato-bold.woff2?cccb897485813c7c256901dbca54ecf2)
			format("woff2"),
		url(fonts/lato-bold.woff?d878b6c29b10beca227e9eef4246111b) format("woff");
	font-weight: 700;
	font-style: normal;
	font-display: block;
}
@font-face {
	font-family: Lato;
	src: url(fonts/lato-bold-italic.woff2?0b6bb6725576b072c5d0b02ecdd1900d)
			format("woff2"),
		url(fonts/lato-bold-italic.woff?9c7e4e9eb485b4a121c760e61bc3707c)
			format("woff");
	font-weight: 700;
	font-style: italic;
	font-display: block;
}
@font-face {
	font-family: Lato;
	src: url(fonts/lato-normal-italic.woff2?4eb103b4d12be57cb1d040ed5e162e9d)
			format("woff2"),
		url(fonts/lato-normal-italic.woff?f28f2d6482446544ef1ea1ccc6dd5892)
			format("woff");
	font-weight: 400;
	font-style: italic;
	font-display: block;
}
@font-face {
	font-family: Roboto Slab;
	font-style: normal;
	font-weight: 400;
	src: url(fonts/Roboto-Slab-Regular.woff2?7abf5b8d04d26a2cafea937019bca958)
			format("woff2"),
		url(fonts/Roboto-Slab-Regular.woff?c1be9284088d487c5e3ff0a10a92e58c)
			format("woff");
	font-display: block;
}
@font-face {
	font-family: Roboto Slab;
	font-style: normal;
	font-weight: 700;
	src: url(fonts/Roboto-Slab-Bold.woff2?9984f4a9bda09be08e83f2506954adbe)
			format("woff2"),
		url(fonts/Roboto-Slab-Bold.woff?bed5564a116b05148e3b3bea6fb1162a)
			format("woff");
	font-display: block;
}
`´´

Also the font files should be removed from the output. Ideally we achieve that somehow by 
changing configuration or hooking the theme code.

From somewhere, there is also fontawesome coming in. These seem to stem from these files:

output/_static/css/theme.css
output/_static/css/badge_only.css