Feature: Klar check whitelisted CVEs and notify on CVE changed Vector (Score)

[HarvyNBB]

### Brief:
Some CVEs when created they have a unique defined vector and base score, However whenever there are any changes noticed for these CVEs, they could end with a changed vector and hence base score.

For instance https://nvd.nist.gov/vuln/detail/CVE-2021-39212
it was published on 09/13/2021 by NVD with

• Base Score: 3.6 LOW

• Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

Then changed on 08/05/2022 by GitHub, Inc. to be

• Base Score: 4.4 MEDIUM

• Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

In case this CVE is whitelisted based on the initial score which is 3.6 Low, there is no way to get notified with this change.

### Feature request:
Klar checks the whitelisted CVE and notifies whenever there is a vector (score) change detected for this CVE since being whitelisted