feat(fingerspelling): add continues fingerspelling animation

[AmitMY]

Fixes #39

For American Sign Language, based on https://fingerspell.net/, I added the transitions for fingerspelling.

The old version (all letters, then a word: "journalizations")

old.webm

1e464244-25db-4154-a245-be50cc725bc4.webm

The new version (all letters, then a word: "journalizations")

new.webm

9fcc9ba1-3359-44c1-acc9-72f80ef5ceae.webm

I kind of like the a-z in the old version more, but spelling a word is nicer in the new version.

What do we like more?

[J22Melody]

I cannot tell what the exact difference is: did you make the transition smoother and the overall speed quicker?

[J22Melody]

the second "journalizations" is a bit confusing for me because it looks like starting with an "i"

[AmitMY]

I cannot tell what the exact difference is: did you make the transition smoother and the overall speed quicker?

I made it so there are only transitions, and each possible transition is coded (A->B, A->C, ....) - that way the spelling is smooth, in place, and faster.

Previous version treated every character as separate a sign, and concatenated them. transitions are generated on the fly

[AmitMY]

Feedback from deaf users: new method should have longer hold between letters. Instead of "AB" + "BC" we should "AB" + pause + "BC". Maybe even not just a static pause, but also a slight scale change, to indicate an abruptness, and to not have multiple frozen frames

New version is also less clear when there is finger contact, like in D or F: