feat: docker image refactor

[juanpicado]

The docker image for verdaccio 5 uses internally yarn pnp wrapper in order to run the execution, I think this a step could be removed but just installing the verdaccio package directly in the docker image context. This PR removes yarn pnp and the project from the docker image entirely, yarn just used for building and pack the project in a tarball in a multi stage step, this reduces considerably the size (~50MB) (it's around 199MB due Node 18 also increases size #3469 nodejs/docker-node#1776, also improve the package npm size so is only packed what's need it.

Also improve the way the plugins are installed, relying only in npm global installation (yarn modern does not have global installation and this was making hard installing plugins.

The verdaccio image for v6 (that uses pnpm) would looks like exactly this one, thus the migration step won't be need it

For testing this improvement uses:

docker run -it --rm --name verdaccio -p 4873:4873 verdaccio/verdaccio:jota-docker-improved

Here an example how to install plugins by creating a new Dockerfile

FROM verdaccio/verdaccio:5
ADD custom-config.yaml /verdaccio/conf/config.yaml  
USER root
RUN npm install --global verdaccio-static-token \
  && npm install --global verdaccio-auth-memory
USER $VERDACCIO_USER_UID

Ref

• How do I install verdaccio plugins on kubernetes? #532
• Add plugins to docker without creating new image? #2042
• plugin-installation in docker #3466
• Document how to install plugins #1677

Follow up of

• feat: update to docker base image to node v18.12.0 #3469
• chore: update yarn 3.x #3394