Move InjectTool URLs outside /image/ location

[bunop]

Is your feature request related to a problem? Please describe.
InjectTool should be accessible without a location, by providing only a domain name

Describe the solution you'd like
The /image/ location should be removed from all its occurrences, from NGINX and from Django configuration files

Describe alternatives you've considered
Things could remain like this, however removing the location will be easier from the user point of view

Additional context

• remove /image/ location from django settings
• remove /image/ location from NGINX
• update docs
• update ansible role