Added tls for http clients (#5766)

* Added global http client

* Added Do func for global http client

* Changed the code to use the global http client

* Fix http client in volume uploader

* Fixed pkg name

* Fixed http util funcs

* Fixed http client for bench_filer_upload

* Fixed http client for stress_filer_upload

* Fixed http client for filer_server_handlers_proxy

* Fixed http client for command_fs_merge_volumes

* Fixed http client for command_fs_merge_volumes and command_volume_fsck

* Fixed http client for s3api_server

* Added init global client for main funcs

* Rename global_client to client

* Changed:
- fixed NewHttpClient;
- added CheckIsHttpsClientEnabled func
- updated security.toml in scaffold

* Reduce the visibility of some functions in the util/http/client pkg

* Added the loadSecurityConfig function

* Use util.LoadSecurityConfiguration() in NewHttpClient func

weed/util/http/client/http_client_name.go

@@ -0,0 +1,14 @@
+package client
+
+import "strings"
+
+type ClientName int
+
+//go:generate stringer -type=ClientName -output=http_client_name_string.go
+const (
+	Client ClientName = iota
+)
+
+func (name *ClientName) LowerCaseString() string {
+	return strings.ToLower(name.String())
+}