Mostly to match everything else.

Mostly so the base URL resolution code can be shared.

To help debug login issues.

Adds a reusable Callback type that is applied to emitter.ts for improved
readability/simplicity.

Adds a str param to common/util::plural for pluralizing a string.
Applies plural to entry.ts.

It's not necessary since we return early if the path starts with a
slash.

In addition, the `settings.write` method now uses shallow merge by default

I added a shallow parameter, because the query should not be extends, but should be replaced directly.

This is for applications like Jupyter that aren't base path agnostic.

It can still be used to check for updates but will not apply them.

For now also remove the update check loop in VS Code since it's
currently unused (update check is hardcoded off right now) and won't
work anyway since it also applies the update which now won't work. In
the future we should integrate the check into the browser update
service.

Provide a way for the shell script running in the docker container to get the url query.

A provider can now be registered on multiple endpoints (or potentially
moved if needed).

- dashboard
- app api

Also confirmed that #1750 is fixed.

- Instead we now use CentOS 7 for the static build to guarantee
  that we only depend on libc v2.17

- For macOS we now pull in a static node binary and bundle that instead.

This way setting --data-dir and --extension-dir in the config file
will work for --install--extension and whatnot.

Closes #1713

Closes #1676

Fixes #1659
Fixes #1642

Closes #1648

Closes #1506