re-use transport and set stronger backwards compatible Ciphers (#19565)

This PR fixes a few things

- FIPS support for missing for remote transports, causing
  MinIO could end up using non-FIPS Ciphers in FIPS mode

- Avoids too many transports, they all do the same thing
  to make connection pooling work properly re-use them.

- globalTCPOptions must be set before setting transport
  to make sure the client conn deadlines are honored properly.

- GCS warm tier must re-use our transport

- Re-enable trailing headers support.

cmd/globals.go

@@ -398,12 +398,8 @@ var (
 
 	globalInternodeTransport http.RoundTripper
 
-	globalProxyTransport http.RoundTripper
-
 	globalRemoteTargetTransport http.RoundTripper
 
-	globalHealthChkTransport http.RoundTripper
-
 	globalDNSCache = &dnscache.Resolver{
 		Timeout: 5 * time.Second,
 	}