Anonymize hosts in subnet health report (#12627)

Ensure that hostnames / ip addresses are not printed in the subnet
health report. Anonymize them by replacing them with `servern` where `n`
represents the position of the server in the pool.

This is done by building a `host anonymizer` map that maps every
possible value containing the host e.g. host, host:port,
http://host:port, etc to the corresponding anonymized name and using
this map to replace the values at the time of health report generation.

A different logic is used to anonymize host names in the `procinfo`
data, as the host names are part of an ellipses pattern in the process
start command. Here we just replace the prefix/suffix of the ellipses
pattern with their hashes.

internal/config/config.go

@@ -374,9 +374,11 @@ func (c Config) RedactSensitiveInfo() Config {
 				}
 			}
 		}
-		nc[configName] = configVals
 	}
 
+	// Remove the server credentials altogether
+	nc.DelKVS(CredentialsSubSys)
+
 	return nc
 }