There was a case with the hashed-password which had multiple equal signs in the
value and it wasn't being parsed correctly. This uses a new function and adds a
few tests.

This lets us re-use the normalized base path so when we expire/clear the
cookie we use the same base path.

It seems reaching into lib/vscode for the types caused tsc to establish
watches that caused it to restart over and over while vscode was
building.

The strategy used here is to symlink it instead which is the same thing
we do for the proxy agent.

Unfortunately since plugins can now override the root this is necessary
or just can't log in.

This will let them throw and show nice errors more easily.

This is mainly so they can get relative paths in their HTML, in
particular code-server's static base so they can use the favicon and
service worker.

So plugins can pass the logger around.

Same reasoning used when exposing Express.

In case they need to map it to something else.

Makes typing much easier. Addresse's Will's last comment.

Next commit will address Will's comments about the typings being weird.

More clear.

See my discussion with Will in the PR.

- Don't use "any" for the API type.
- Remove everything from the Coder API that can eventually be done
  through the VS Code API.
- Move the event emission to our own client to minimize patching.