docs(embedding_deno): added an overview of all deno crates and what they do.

[NinekoTheCat]

Closes denoland/deno-docs#109

Adds a new chapter that clarifies what deno crates do and links to them.

Makes it easier to figure out where to even begin constructing your ideal version of Deno.

[CLAassistant]

All committers have signed the CLA.

[NinekoTheCat]

Crates are documented in their own READMEs in their repos/dirs. Do we want to duplicate those docs in this format? cc @ry @piscisaureus @bartlomieju

A list of all deno related crates are also available in https://crates.io/teams/github:denoland:engineering

I'd argue that it's better to document it in the manual for easier access. No one wants to scavange for this kind of information.

[bartlomieju]

These crates are documented in the READMEs in their own repos/dirs. Do we want to duplicate those docs in this format? cc @ry @piscisaureus @bartlomieju

A list of all deno related crates are also available in https://crates.io/teams/github:denoland:engineering

I think it's fine to document them here too

[crowlKats]

there are other crates as well, like v8 & urlpattern, and probably a bunch more i am forgetting