* NodeJS: v16
* NPM: v8
* Jest: v27
* Mongoose: v6

And fix some small issues along the way

* remove 'renders a todo add' test since it was a) the wrong place
  and b) already implemented by PR #36
* fix indentation and make sure that there is actually a user that
  the test tries to delete

* fix file name typo
* remove logs in test do reduce noise
* prevent 'connection established' log in test mode to reduce noise
* rename test to make it more obvious that it does not require (or create)
  a user object

* update mongoose, jest and nodemon to address security alerts triggered
  by dependabot
* 'test' target had a bug introduced by using wrong syntax
* renamed server scripts to clarify the distinction between invocations
  in local development, CI and actual operations

* adjust mongoose configuration
* documents more make targets in readme
* applied npm scripts convention of the client to the corresponding
  server scripts in order to be more consistent (`start` is now meant
  for local development)

* keep both in gitignore, since the default still exist

* change behaviour so that service still comes up regardless whether db connection
  can be established or not (see 12-Factor-App) - loosely tight to backing service
* instead, it will log to stderr hinting this issue
* successful port binding is still required

* introduce a test on the server to see if user creation works (backend process <-> db only;
  still needs a test that involves the router, too)
* main server process is no connection-aware and wont start if database is not reachable
* some renaming, cause it's more descriptive
* unify quote usage

* update deps to latest and pin min node & npm version
* checkin lock files
* make server serve client to merge both into one in order to reduce complexity
* adjust CSP accordingly

src: https://github.com/aamirpinger/todo-app-client-server-kubernetes/commit/93be212a344ea910b0a13f1110975bfdfd306f3a