Support Bundle can include unprotected HTTP proxy server password

When Nexus is configured with an HTTP proxy server that has username and password, then the system properties `http.proxyPassword` and `https.proxyPassword` get set to the plain text proxy server password.

The sysinfo report included in the support bundle can include these plain text system property values. Suggest these values be replaced with some known text instead to protect the password from being transmitted in the support bundle.