Add more fields to netsparker plugin

[dormi]

Steps to reproduce

Upload a netsparker output xml file, generated with the "detailed" option (this detailed xml option is relatively new)
(zipped sample attached)
php.testsparker.com - Vulnerabilities List - Detailed (XML).xml.zip

Expected behavior

The following fields should be parsed by Dradis:

<impact>
<actionsToTake>
<requiredSkillsForExploitation>
<externalReferences>
<remedyReferences>
<extrainformation>

Actual behavior

We are not importing those fields

System configuration

Dradis version: CE 3.9 / PRO 2.9

Ruby version: 2.4

OS version: Any

[microidz]

Hi!

Would be nice if you could also include the following filelds:

Thanks!