docs: clarify Alpine install path in install.md

feat(testing): add unit tests for constants

docs(README.md): update to include requirements

feat(testing): add unit tests for src/common/http

Update README.md to include requirements

Promote ease of adoption by placing the requirements in the README at the root folder level.

This fixes the lint script but unfortunately breaks my editor.

Somehow I managed not to commit this earlier.

This can affect the test behavior and results.

Otherwise it consumes the body and plugins won't be able to do things
like proxy POST requests.

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.

This way tests that import the http utilities but not the routes won't
error due to missing types.

So plugins can pass the logger around.

Same reasoning used when exposing Express.

This is used by some of our services.

In case they need to map it to something else.

The other plugins in my path were causing the tests to fail.