Fix: Refactoring, correction of typos, set Licence

Author: Vladislav Shchetinin

gpcontrib/gp_relsizes_stats/LICENCE

@@ -5,7 +5,7 @@ EXTVERSION      = 1.3
 DATA            = $(wildcard sql/*--*.sql)
 REGRESS         = grants gp_relsizes_stats
 REGRESS_OPTS    = --inputdir=test/
-PGFILEDESC      = "gp_relsizes_stats - an extension to track table on-disc sizes in greenplum"
+PGFILEDESC      = "gp_relsizes_stats - an extension to track table on-disc sizes in Cloudberry"
 PG_CXXFLAGS     += $(COMMON_CPP_FLAGS)
 ifdef USE_PGXS
 PG_CONFIG = pg_config

gpcontrib/gp_relsizes_stats/Makefile

@@ -1,3 +1,22 @@
+<!--
+  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.
+-->
+
 # gp_relsizes_stats: Table sizes monitoring tool for Cloudberry
 
 ### Features
@@ -11,16 +30,15 @@ gp_relsizes_stats is an extension for the Cloudberry database that calculates an
 At the moment, the program is being tested only for Cloudberry and Linux.
 
 ### Installation
-Install from source:
-```
-git clone git@github.com:open-gpdb/gp_relsizes_stats.git
-cd gp_relsizes_stats
-# Build it. Building would require GP installed nearby and sourcing greenplum_path.sh
-source <path_to_gp>/greenplum_path.sh
-make && make install
+This extension is part of the Cloudberry monorepo under `gpcontrib/gp_relsizes_stats`.
+
+Build and install from the Cloudberry monorepo root:
+```bash
+make -C gpcontrib/gp_relsizes_stats
+sudo make -C gpcontrib/gp_relsizes_stats install
 ```
 
-### Confguration
+### Configuration
 gp_relsizes_stats configuration parameters:
 | **Parameter** | **Type**     | **Default**  | **Description**  |
 | ---------------- | --------------- | ------------ | ------------ |