Affects: users of USES=nodejs, www/node*, www/npm* and www/yarn*

Author: sunpoet@FreeBSD.org

Reason: 
  The current USES=nodejs has the following issues:
  - www/node is not the default version while www/node16 is.
  - It also means inconsistent naming of node ports.
  - www/npm duplicates with www/npm-node16.
  - www/yarn duplicates with www/yarn-node16.

  The notable changes are introduced to fix the above issues:
  - Rewrite Mk/Uses/nodejs.mk.
  - Add new LTS version of nodejs (www/node18).
  - Add new current version of nodejs (www/node19).
  - Change default nodejs version from 16 to 18 (latest LTS),
  - Use consistent naming for all supported node versions.
  - Convert www/node, www/npm and www/yarn to meta ports.

  After these changes:
  - All supported node versions are named as node{14,16,18,19}.
  - www/node is a meta port which depends on the default version
    (e.g. www/node18)
  - www/npm is a meta port which depends on the default version
    (e.g. www/npm-node18)
  - www/yarn is a meta port which depends on the default version
    (e.g. www/yarn-node18)

Affects: users of www/node*, www/npm*, www/yarn*

Author: mfechner@FreeBSD.org

Reason: 
  The port framework was updated to use a default version for nodejs.
  The default version is pointing to the latest LTS version which is
  currently version 16.
  You can overwrite this by defining in /etc/make.conf, e.g. version 17:
  DEFAULT_VERSIONS=nodejs=17

  Or if you would like to stick always to the current version use:
  DEFAULT_VERSIONS=nodejs=current

  If you would like to use yarn or npm together with nodejs version 17,
  just install the package that is pulling the wanted dependency to nodejs:

  # pkg install yarn-node17
  # pkg install npm-node17