Add Apache RAT plugin information for licensing reasons

[StrongestNumber9]

Description

https://creadur.apache.org/rat/apache-rat-plugin/

Use case or motivation behind the feature request

Force licenses to exist in appropriate files

Related issues

Additional context

Something like

<plugin>
  <groupId>org.apache.rat</groupId>
  <artifactId>apache-rat-plugin</artifactId>
  <version>0.16.1</version>
  <inherited>false</inherited>
  <executions>
    <execution>
      <phase>test</phase>
      <goals>
        <goal>check</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <addDefaultLicenseMatchers>false</addDefaultLicenseMatchers>
    <addDefaultLicenses>false</addDefaultLicenses>
    <families>
      <family>
        <id>Teragrep</id>
        <name>Teragrep Affero General Public License v3</name>
      </family>
    </families>
    <licenses>
      <license>
        <all>
          <copyright>
            <owner>INSERT LICENSE HERE</owner>
            <start>INSERT YEAR HERE</start>
          </copyright>
          <text>INSERT TEXT HERE</text>
        </all>
        <family>Teragrep</family>
      </license>
    </licenses>
    <consoleOutput>true</consoleOutput>
    <excludeSubProjects>false</excludeSubProjects>
    <excludes>
      <!-- git -->
      <exclude>.git/**</exclude>
      <exclude>.gitattributes</exclude>
      <exclude>.gitignore</exclude>
      <exclude>.gitmodules</exclude>
      <!-- ci -->
      <exclude>.github/**</exclude>
      <exclude>toolchains.xml</exclude>
      <exclude>settings.xml</exclude>
      <exclude>pom.xml</exclude>
      <!-- readme -->
      <exclude>README.adoc</exclude>
    </excludes>
  </configuration>
</plugin>