new icon: sourceengine (original, original-wordmark, plain, plain-wordmark) (#2211)

* new icon sourceengine

* Apply suggestions from code review

- Add missing SVG and font versions.
- add "javascript" tag
- add "source engine" altname

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Co-authored-by: Jørgen Kalsnes Hagen <43886029+Snailedlt@users.noreply.github.com>

icons/sourceengine/sourceengine-plain.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128"><path fill="#f79a10" d="m104.564 4.343-63.813.363c-13.179-.677-26.16 2.55-37.387 9.008l.011.01c-5.867 3.203-3.602 12.117 3.083 12.129 1.866 0 3.53-.79 4.709-2.043a55.05 55.05 0 0 1 47.029-2.464c28.133 11.546 41.626 43.84 30.08 71.973a54.8 54.8 0 0 1-13.307 19.27l.054.069c-6.767 3.899 4.552 15.634 8.693 9.013A67.4 67.4 0 0 0 99.93 98.103c.262-.63 26.411-64.325 26.475-64.496 4.458-10.876-.742-23.307-11.616-27.77-2.934-1.206-5.675-1.483-8.838-1.494zM32.36 37.063c-14.053 0-28.49 4.304-28.49 21.019 0 11.52 10.378 15.194 20.762 17.477 12.918 2.784 20.39 4.683 20.39 10.128 0 6.336-6.587 8.363-11.776 8.363-7.094 0-13.675-3.168-13.803-11.02H2.351c.763 17.345 15.573 23.04 30.773 23.04 14.939 0 29.883-5.567 29.883-22.788 0-12.16-10.256-15.958-20.768-18.363-10.256-2.405-20.39-3.29-20.39-9.75 0-5.317 5.953-6.08 10.011-6.08 6.453 0 11.77 1.905 12.277 8.865h17.094c-1.387-16.08-14.56-20.89-28.87-20.89z"/></svg>