Allow website jobs to choose hugo version

[victorb]

From ipfs-inactive/docs#68 (comment)

Currently, websites using jenkins to deploy to ipfs cannot chose which hugo version to use.

What we want to enable, is that the website() function in the ipfs/jenkins-libs repository, should accept a hugo_version argument, where projects can specify exactly which hugo version to use.

For this to work, we should tag our ci-websites image with the version from hugo, build and push those to Docker Hub.