ZAP wrapper shall use template data

[winzj]

Situation

With #3545 we are now able to use template data inside pds-solutions.

Wanted

Make use of the template data to enable script authentication in pds-owaspzap solution.

Solution

• the script file must be correctly loaded from the extracted directory
• the template webscans always use the template variables username and password for pds-owaspzap solution
• make sure the path to the script is exported as environment variable in the owasp-zap.sh script if it exists
• document the following requirements on the pds-solution side:
  • the script file is always called script.groovy
  • the variables username and password must be present for template webscans. The value of username can be any user identification like an ID, an email or a name.