Upgrade to the last django LTS version (2.2)

[bunop]

Is your feature request related to a problem? Please describe.
Django 1.11 will reach its end of life in April 2020. Before this date will be useful to upgrade django to the last version in order to facilitate future maintenance

Describe the solution you'd like
Change django version in requirements.txt and fix all test that will not works. Url refactoring could be addresses in order to exploit the last django features

Describe alternatives you've considered
This task should be addressed on the final stages of InjectTool development

Additional context
Those are the steps that need to be addressed:

• Change django version in requirements.txt an set to the actual LTS version (2.2)
• Apply migrations where possible
• Fixing things after migrations (will 3rd party modules works with new django version?)
• Upgrade urls.py sintax accordingly django-2.2
• Test things as usual
• General test of InjectTool (functional testing?)