Upload / Reimport of reports should consider severity

[manuel-sommer]

Is your feature request related to a problem? Please describe Some tools update the severity of findings. Here some examples:

• DependencyTrack tracks CVEs. Due to false positive reportings, CVEs are closed as rejected e.g. https://nvd.nist.gov/vuln/detail/CVE-2021-20095. Then, DependencyTrack updates the severity of these vulnerabilities to "unassigned". This is basically a "Informational" finding in DefectDojo. However, the new severity is not updated when DependencyTrack syncs the finding to DefectDojo and the finding remains open.
• DrHeader supports the way to set custom severities. If this changes, the severity is not updated in DefctDojo https://github.com/Santandersecurityresearch/DrHeader/pull/170

Describe the solution you'd like The severity is updated for all findings when they are uploaded (upload or reimport). This includes an SLA adjustment.

[manuel-sommer]

https://github.com/DefectDojo/django-DefectDojo/issues/7728