Move the wisdom default archetype to the extensions directory (instead of core)

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Fix encoding issue

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Documentation related to #13

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>
Document the Maven archetype

Signed-off-by: Clement Escoffier <clement.escoffier@gmail.com>