XWIKI-3977: Create a Maven Archetype to make it easy to create XWiki Macros

xwiki-platform-tools/pom.xml

...orm-tools/src/main/resources/META-INF/maven/archetype.xml

...form-tools/src/main/resources/archetype-resources/pom.xml

...etype-resources/src/main/java/ExampleMacroParameters.java

...hetype-resources/src/main/java/internal/ExampleMacro.java

...type-resources/src/main/resources/META-INF/components.txt

...ces/archetype-resources/src/test/java/RenderingTests.java

...rces/archetype-resources/src/test/resources/example1.test