Provide common workspace setup

[josephperrott]

Provide a common importable function to setup the WORKSPACE for downstream repositories, retrieving necessary dependencies and setting up things like node modules.

This would allow us to sychronize the versions of node and rules_nodejs being used by repositories.

Before:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

# Fetch rules_nodejs so we can install our npm dependencies
http_archive(
    name = "build_bazel_rules_nodejs",
    sha256 = "5c40083120eadec50a3497084f99bc75a85400ea727e82e0b2f422720573130f",
    urls = ["https://github.com/bazelbuild/rules_nodejs/releases/download/4.0.0-beta.0/rules_nodejs-4.0.0-beta.0.tar.gz"],
)

load("@build_bazel_rules_nodejs//:index.bzl", "node_repositories", "yarn_install")

node_repositories(
    node_repositories = {
        "14.17.0-darwin_amd64": ("node-v14.17.0-darwin-x64.tar.gz", "node-v14.17.0-darwin-x64", "7b210652e11d1ee25650c164cf32381895e1dcb3e0ff1d0841d8abc1f47ac73e"),
        "14.17.0-linux_amd64": ("node-v14.17.0-linux-x64.tar.xz", "node-v14.17.0-linux-x64", "494b161759a3d19c70e3172d33ce1918dd8df9ad20d29d1652a8387a84e2d308"),
        "14.17.0-windows_amd64": ("node-v14.17.0-win-x64.zip", "node-v14.17.0-win-x64", "6582a7259c433e9f667dcc4ed3e5d68bc514caba2eed40e4626c8b4c7e5ecd5c"),
    },
    node_version = "14.17.0",
)

yarn_install(
    name = "npm",
    package_json = "//:package.json",
    yarn_lock = "//:yarn.lock",
)

After:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

# Fetch rules_nodejs so we can install our npm dependencies
http_archive(
    name = "angular-dev-infra",
    sha256 = "...",
    urls = ["https://github.com/angular/dev-infra-private-builds/..."],
)