Update guss webfonts & serve WOFF 2.0 fonts

- [new] Use the latest set of fonts from Commercial type /cc @rich-nguyen sorry it's even bigger than the previous one and should add 30 MB to builds
- [new] Serve WOFF 2.0 fonts. Browsers supporting WOFF 2.0 get a larger character set than WOFF 1.0, for a smaller file size (~200 vs ~214 KB).
- [new] Serve fonts without kerning tables.

Before (WOFF): 392,422 bytes
After: WOFF: 214,910 bytes | WOFF 2.0: 200,010 bytes

This is almost 50% reduction, with fonts actually looking better and with more characters in the case of WOFF.

/cc @phamann 

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