build: Add category to module definition

Adds a category as a parameter for jboss-modules-maven-plugin to
identify usage of a module. Category can be one of:

  common
    - module is used inside JBoss instance and in standalone tools
    - default value

  tools
    - module is used only in standalone tools

Change-Id: Ief6e14398bec4378c2153514bb69667835c3d331
Related-To: https://bugzilla.redhat.com/1109871
Signed-off-by: Martin Perina <mperina@redhat.com>