Freeze Nuxeo packages installation

In the context of Docker, when using an automatic mp-hotfix command during the build it increases the image footprint a lot.

For instance, today, on a 9.10 with 30 HF:

• Without mp-hotfix executed: 199M
• After mp-hotfix executed: 1.5G

Footprint increases a lot because of all the packages store/backup folders required to be able to rollback installation, ...
In a Docker context, we could imagine that we are building an image per assembly and we'll never manage to install/uninstall package manually post image build.

Cleaning manually those folders with:

rm -rf packages/backup packages/tmp && find packages/store/* ! -name 'package.xml' -type f -exec rm -f {} +

leads to an unstable state, but it works as a workaround to optimize the size (the same way apt's caches are deleted...)

We need a better solution, in order to:

• have a proper nuxeoctl command that cleanup those folders
• either
  • flag Nuxeo as a "frozen" distribution that cannot make modifications to packages
  • be able to do package operations on that base-assembly (add/remove new packages), and keep track of what packages were installed before