Allowed for multiple service handling and fixed in_progress update

Changes:

Added MAG tempalte
Removed MAG from other templates
Allowed to handle more than one service at a time (#217)
Added a test to avoid updating service's state to in_progress multiple times #285

PR checklist

[X] This comment contains a description of changes (with reason).
[X] Make sure your code lints (black and flake8).
If a new tamplate was added make sure:
- [X] Template's schema is added in templates/services.json.
- [X] Template's pipeline's documentation in assets/reports/md/template.md is added.
- [X] Results Documentation in assets/reports/results/template.md is updated.
[x] CHANGELOG.md is updated.
[ ] README.md is updated (including new tool citations and authors/contributors).
[ ] If you know a new user was added to the SFTP, make sure you added it to templates/sftp_user.json