Remove not existing module archetype-testing from documentation

Author: slawekjaranowski

src/site/apt/index.apt

@@ -76,8 +76,6 @@ mvn archetype:generate
 | {{{./archetype-models/}archetype-models}}                 | Descriptors classes and reference documentation,
 *-----------------------------------------------------------+----------------+
 | {{{./archetype-common/}archetype-common}}                 | Core classes,
-*-----------------------------------------------------------+----------------+
-| {{{./archetype-testing/}archetype-testing}}               | Components used internally to test Maven Archetype,
 *-----------------------------------------------------------+----------------+
 
  Some archetypes are also provided by Maven: see {{{/archetypes/}Maven Archetype Bundles}}.