Host aspect-build/rules_deno

[alexeagle]

I've been working with @TheGrizzlyDev to provide a toolchain for running https://deno.land/ programs under Bazel.
This is an alternative to NodeJS for running JavaScript code outside a browser.

It meets the criteria https://bazel-contrib.github.io/SIG-rules-authors/hosting-policy.html#adding-criteria:

1. License is Apache 2
2. JavaScript is the most popular programming language, and Deno is the second-most-popular (?) runtime for it after NodeJS. Not clear how many adopters this ruleset would have at the beginning though.
3. Point of contact is myself
4. Has examples, generated docs, and testing on GH actions. More to come as custom rules are added.
5. Will agree to reply to issues/PRs in 2-3 weeks
6. At least myself and @TheGrizzlyDev will review/approve PRs
7. Uses the rules-template release mechanism which is semver
8. Works with Bazel 5

[alexeagle]

Discussed in the SIG meeting today: we're not sure Deno is widely-used enough yet, and it seems like @TheGrizzlyDev and I could just host this in some other neutral location.
We should follow-up with Helen about where that is.