Increase warning level for javascript CVEs

Set minimium serverity for which CVEs are reportet to high.

Minimum severity to treat as an error, default is low (info, low, moderate, high, critical)

This is to avoid too many alerts on issues which do not need our attention. We only use javascript on Clients except for asset building. Therefor for us high/criticial issues will be sufficient to attentend to. Additionally in many cases we simply ignored the Alert anyway.

Note: We still want to be alerted on issues in dev-dependencies as we really need to know if our local development systems have been compromised by malware :)