This commit adds "std/_util/os.ts" module which contains
common os detection logic and is browser compatible.
Co-authored-by: Nayeem Rahman <nayeemrmn99@gmail.com>
* Prepend underscores to private modules
* Remove collectUint8Arrays() It would be a misuse of Deno.iter()'s result.
* Move std/_util/async.ts to std/async
* Move std/util/sha*.ts to std/hash