Now we support pretty much every variable under the sun along with
$NO_PROXY all correctly and with minimal code on our end.

Just convention, see https://golang.org/pkg/net/http/#ProxyFromEnvironment

refactor (vscode): migrate from submodule to subtree

git-subtree-dir: lib/vscode
git-subtree-split: e5a624b788d92b8d34d1392e4c4d9789406efe8f

feat(local development): add vscode:clean script

This should prevent us from generating different diffs and adding noise
to our PRs. Patience seems like a good one; it generated a diff that I
felt was easier to read in the case of the yarn.lock optionator section.

This is so it can be used in VS Code. Don't tell anyone but I forgot to
run `yarn ci`.

cli: add --home flag to customize "Go Home" button

This allows bypassing the last opened behavior for certain cases where that's not desirable.

Fixes #1951