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/endpoint.go

@@ -1205,7 +1205,7 @@ func GetProxyEndpoints(endpointServerPools EndpointServerPools) []ProxyEndpoint
 
 			proxyEps = append(proxyEps, ProxyEndpoint{
 				Endpoint:  endpoint,
-				Transport: globalProxyTransport,
+				Transport: globalRemoteTargetTransport,
 			})
 		}
 	}