add UUID module supporting v4

[lucascaro]

Fixes #403

• add generation and validation of uuid v4
• tests for v4
• uuid v1
• uuid v3
• uuid v5
• use crypto. getRandomValues()

[CLAassistant]

All committers have signed the CLA.

[axetroy]

Why use such a strange directory structure?

- uuid
  - tests
    - v4
     - generate.ts

[lucascaro]

Why use such a strange directory structure?

- uuid
  - tests
    - v4
     - generate.ts

I added /tests/ because I prefer to keep all test files separated from the code.

v4 in there is to be prepared to add tests for v1, v3, and v5 while keeping them clearly separated.

generate vs validate is personal preference too: test files that deal with a single concern or topic.

I'm totally open to suggestions if this doesn't follo deno_std best practices

[hayd]

Just to confirm, this is based of this gist? https://gist.github.com/jed/982883#gistcomment-2886092

Is that not a concern? (I am a little confused whether this was code golf.)

[lucascaro]

@hayd the code in my module was originally based off a version in that gist. The current iteration looks different.
I think at this point it's important to focus on the api this is exposing rather than the specific implementation since the implementation can change any time, but if this makes it into deno_std, other modules will depend on it maintaining a compatible api.

[ry]

LGTM - thanks @lucascaro ! I think we can iterate further in the repo