fix routing issue for esoteric characters in gorilla/mux (#8967)

First step is to ensure that Path component is not decoded
by gorilla/mux to avoid routing issues while handling
certain characters while uploading through PutObject()

Delay the decoding and use PathUnescape() to escape
the `object` path component.

Thanks to @buengese and @ncw for neat test cases for us
to test with.

Fixes #8950
Fixes #8647

cmd/routers.go

@@ -84,7 +84,7 @@ var globalHandlers = []HandlerFunc{
 func configureServerHandler(endpointZones EndpointZones) (http.Handler, error) {
 	// Initialize router. `SkipClean(true)` stops gorilla/mux from
 	// normalizing URL path minio/minio#3256
-	router := mux.NewRouter().SkipClean(true)
+	router := mux.NewRouter().SkipClean(true).UseEncodedPath()
 
 	// Initialize distributed NS lock.
 	if globalIsDistXL {