The minimum required nodejs version for developing swh-web is 12.x but it reached EOL and is no longer maintained.

Also some of our javascript dependencies now require nodejs >= 14.x to be installed so it is time to upgrade it.

To do so we must:

• upgrade nodejs in the swh/stack docker image used in our docker-compose environment
• upgrade nodejs in the docker images used by Jenkins
• bump nodejs version in package.json file of swh-web and update its readme
• update developer documentation about the minimum required nodejs version