Manual installation procedure is annoying

[amotl]

Please resolve the manual installation procedure. Thanks!

node-blue/README.md

Lines 32 to 38 in c48f859

	There is currently a little manual post-setup procedure.
	```shell
	node-blue setup
	wget https://github.com/daq-tools/node-blue/raw/refs/heads/main/package.json
	wget https://github.com/daq-tools/node-blue/raw/refs/heads/main/node.importmap
	npm install
	```

node-blue/.github/workflows/tests.yml

Lines 68 to 71 in c48f859

	# TODO: This command should write a `package.json`, then invoke `npm install`.
	node-blue setup
	# TODO: Refactor to `node-blue setup`, see above.
	npm install

Originally posted by @amotl in #84