dynamic objectstore password

[jeromecremers]

Objectstore passwords (obviously) differ among tenants/projects. This commit handles them dynamically. Just fill in the name of the environment variable holding the password in the config.ini file.

[Lytrix]

Could you do a:

git stash
git pull
git merge stash 

So this code is added into the new release? The directory structure is now changed to state: import datapunt_processing, so the locations are now out of sync.

[jeromecremers]

Done. I don't have write access so I can't resolve the conflicts mentioned below. Let me know if you need help.