Import SVG2 tests

The SVG WG has an old abandoned svg2-tests repo at https://svgwg.org/hg/svg2-tests/; given the WG seem to have no interest in maintaining a testsuite currently, we should import them into our svg directory for the sake of having a maintained SVG testsuite somewhere.

Given the amount of folders that lead to readme or .emtpy files, the files that may or may not be tests in the repo are:

./contributors/ed/submitted/filters-quality-01-ref.svg
./contributors/ed/submitted/filters-quality-01.svg
./contributors/ed/submitted/filters-saturate-01-ref.svg
./contributors/ed/submitted/filters-saturate-01.svg
./contributors/ed/submitted/filters-saturate-02-ref.svg
./contributors/ed/submitted/filters-saturate-02.svg
./contributors/ed/submitted/filters-saturate-03-ref.svg
./contributors/ed/submitted/filters-saturate-03.svg
./contributors/ed/submitted/filters-saturate-04-ref.svg
./contributors/ed/submitted/filters-saturate-04.svg
./contributors/ed/submitted/grumpycat.jpg
./contributors/smailus/incoming/SVG2 TestTemplate.svg
./contributors/smailus/incoming/Test - SVG2 - text-text-textLength/text-text-01-b.html
./contributors/smailus/incoming/Test - SVG2 - text-text-textLength/text-text-01-b_files/testharnessreport.js
./contributors/smailus/incoming/Test - SVG2 - text-text-textLength/text-text-01-b_files/text-text-01-b-SVG1.2version.png
./contributors/smailus/incoming/Test - SVG2 - text-text-textLength/text-text-01-b_files/text-text-01-b.png
./contributors/smailus/incoming/Test - SVG2 - text-text-textLength/text-text-01-b_files/text-text-01-b.svg
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/testharnessreport.js
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength-test 1 2 - IE.png
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength-test 5 - FF.png
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength-test 6 - IE.png
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength.cdr
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength.png
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan-files/text-tspan-textLength.svg
./contributors/smailus/incoming/Test - SVG2 - text-tspan-textLength/text-tspan.html
./contributors/smailus/submitted/SVG2 TestTemplate.svg
./contributors/tavmjong/incoming/reftest/svg-matrix-four-color-ref.svg
./contributors/tavmjong/incoming/svg-matrix-001.svg
./contributors/tavmjong/incoming/text-dx-001.svg
./contributors/tavmjong/submitted/fonts/FreeMono.woff
./contributors/tavmjong/submitted/fonts/FreeMonoBold.woff
./contributors/tavmjong/submitted/fonts/FreeMonoBoldOblique.woff
./contributors/tavmjong/submitted/fonts/FreeMonoOblique.woff
./contributors/tavmjong/submitted/fonts/FreeSans.woff
./contributors/tavmjong/submitted/fonts/FreeSansBold.woff
./contributors/tavmjong/submitted/fonts/FreeSansBoldOblique.woff
./contributors/tavmjong/submitted/fonts/FreeSansOblique.woff
./contributors/tavmjong/submitted/fonts/FreeSerif.woff
./contributors/tavmjong/submitted/fonts/FreeSerifBold.woff
./contributors/tavmjong/submitted/fonts/FreeSerifBoldItalic.woff
./contributors/tavmjong/submitted/fonts/FreeSerifItalic.woff
./contributors/tavmjong/submitted/template_001.svg
./contributors/tavmjong/submitted/template_001_ref.svg
./contributors/tavmjong/submitted/template_automated.svg
./contributors/tavmjong/submitted/template_automated_ref.svg
./contributors/tavmjong/submitted/template_visual.svg
./contributors/tavmjong/submitted/template_visual_ref.svg
./contributors/tavmjong/submitted/transforms-basic-001-prefixed.svg
./contributors/tavmjong/submitted/transforms-basic-001-ref.svg
./contributors/tavmjong/submitted/transforms-basic-001.svg
./contributors/tavmjong/submitted/transforms-basic-002-prefixed.svg
./contributors/tavmjong/submitted/transforms-basic-002-ref.svg
./contributors/tavmjong/submitted/transforms-basic-002.svg
./contributors/tavmjong/submitted/transforms-basic-003-prefixed.svg
./contributors/tavmjong/submitted/transforms-basic-003-ref.svg
./contributors/tavmjong/submitted/transforms-basic-003.svg

It certainly looks like some of those are not tests (being resources like the fonts which may or may not actually be used by any of the tests). Equally, some of them are CSS tests and should go into https://github.com/w3c/csswg-test.