Implement Hebrew Font Shaper

[JimBobSquarePants]

Now that #198 has been merged the fundamental infrastructure is there to allow support for Bidi text rendering however we still lack some dedicated shapers. This issue tracks the development of a Hebrew shaper.

Guide.
https://github.com/n8willis/opentype-shaping-documents/blob/master/opentype-shaping-hebrew.md

HarfBuzz Implementation
https://github.com/harfbuzz/harfbuzz/blob/main/src/hb-ot-shape-normalize.cc
https://github.com/harfbuzz/harfbuzz/blob/main/src/hb-ot-shaper-hebrew.cc

[stefannikolei]

Wanted to tackle a new challenge..

Probably need to read that "guide" a few times more to find it helpful. Especially when looking at that HarfBuzz implementation.. Could not connect the dots by now...

Doing a lil research for more sources. But it really seems that Harfbuzz is one of the only libs to handle Hebrew shaping out there.

This lib claims it has implemented Hebrew, but has no specific Shaper. https://github.com/yeslogic/allsorts/blob/master/src/scripts/mod.rs It seems it integrated it into the default shaper