Big update

[dcastelaosua]

This PR includes a long list of improvements for dhis2-tools-ng made in the SolidLines repo.

New features include:

• credentials for munin and glowroot
• centralize logging via journald
• export logs from the logger

Several bugs have been fixed and scripts' robustness has been improved.

[davinerd]

We decided to split this PR in multiple, single ones for better code review.