We should stop using/displaying the NVD severity in the Security Tracker. Anyone
is free to look up whatever external data source they want, but we should not
give NVD legitimacy by showing in the Security Tracker.

Just to give a bit of context:

One of the problem publishing severities as-is is looking less secure
while actually not true.
For example publishing docker images to quay.io for several distribution
will make debian look worse than others.

|             Tag                    |     Last Modified     |    
Security Scan      |
-----------------------------------------------------------
| ubuntu-20.04-java |     an hour ago        |       5 Medium            |
|      debian-11-java     |     2 hours ago        |            1
High               |
|            centos-7           |    6 hours ago |         
Passed               |

Here debian reports
https://security-tracker.debian.org/tracker/CVE-2021-33574 as High but
this CVE only seem to affect glibc 2.32 & 2.33 while all versions of
debian (but sid) have 2.31 or earlier so shouldn't be affected.

RedHat/Fedora bug tracker clearly stated that and Ubuntu has the CVE in
"Triage" status so it doesn't show up in the scan report in quay.io (and
I guess in many other scanning tool which rely on distribution security
bug trackers)