Separate SVG & CSS filters into their own files

[jonathantneal]

Some of the plugins in this repo use SVG filters, which is awesome! However, those filters are difficult to edit because they are hard-coded as strings in the plugin repo. How would you feel about breaking them out into their own files and pulling them in via fs.readFileSync? Similarly, for filters that leverage CSS, how would you feel about breaking those out into their own files?

[azat-io]

Yeah. We can clear it.
Also Autoprefixer can make SVG filter from filter property.