start: add path for addons directory that can be different from odoo bin path. try to give it a reasonable value, it is the one from that work in our docker, but it can be changed with an environment variable

In the loop:
- Rename the "module" variable to "module_path".
- Set up a new "module" variable that contains nothing but the actual module
  name.

keep .hg* for .hgignore and .hgtags

With a single underscore, the "link target" system is used, resulting in
conflicts when the same version name is shared by 2 repos.

docker_build: copy modules (defined in setup.cfg in superproject to a new directory for docker to do)

create_documentation: only create documentation for used modules, reusing the setup.cfg key defined for create_archive if it is present