* 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

* npm is a symlink in the node artifact, so, extracting only the symlink
  is no good if its actual target is not there. Now, the whole `node_modules`
  is extracted instead, and a symlink is created explicitly
* remove wildcards to avoid necessity of `--wildcards`, which is not
  supported by BSD tar
* minor phrasing

* 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)

* tech stack can be installed locally and will be used by app-related
  targets if available
* bumped minimal required npm version to 6.14 for server and client

* readme files for the repository and the app
* makefile ans the main entry and documentation
* remove create-react-app from client code