use dnscache resolver for resolving command line endpoints (#14135)

this helps in caching the resolved values early on, avoids
causing further resolution for individual nodes when
object layer comes online.

this can speed up our startup time during, upgrades etc by
an order of magnitude.

additional changes in connectLoadInitFormats() and parallelize
all calls that might be potentially blocking.

cmd/common-main.go

@@ -678,7 +678,7 @@ func handleCommonEnvVars() {
 		for _, endpoint := range minioEndpoints {
 			if net.ParseIP(endpoint) == nil {
 				// Checking if the IP is a DNS entry.
-				addrs, err := net.LookupHost(endpoint)
+				addrs, err := globalDNSCache.LookupHost(GlobalContext, endpoint)
 				if err != nil {
 					logger.FatalIf(err, "Unable to initialize MinIO server with [%s] invalid entry found in MINIO_PUBLIC_IPS", endpoint)
 				}