[Plugin] Add BE plugin framework (#2348) (#2618)

Support BE plugin framework, include:

* update Plugin Manager, support Plugin find method
* support Builtin-Plugin register method

* plugin install/uninstall process
	* PluginLoader:
		* dynamic install and check Plugin .so file
		* dynamic uninstall and check Plugin status
	* PluginZip:
		* support plugin remote/local .zip file download and extract

TODO:

* We should support a PluginContext to transmit necessary system variable when the plugin's init/close method invoke

* Add the entry which is BE dynamic Plugin install/uninstall process, include:
	* The FE send install/uninstall Plugin statement (RPC way)
	* The FE meta update request with Plugin list information
	* The FE operation request(update/query) with Plugin (maybe don't need)

* Add the plugin status upload way
* Load already install Plugin when BE start

be/test/plugin/example/plugin_example.cpp

@@ -0,0 +1,51 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include <iostream>
+
+#include "plugin/plugin.h"
+
+namespace doris {
+
+int init(void *) {
+    std::cout << "this is init" << std::endl;
+    return 1;
+}
+
+int close(void *) {
+    std::cout << "this is close" << std::endl;
+    return 2;
+}
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+    
+declare_plugin(PluginExample) {
+    nullptr,
+    &init,
+    &close,
+    3,
+    nullptr,
+    nullptr
+} declare_plugin_end
+
+#ifdef __cplusplus
+}
+#endif
+
+}