Add tempplate constants defining elements the mp template will work with.
Move SP-vCPE template constants into 'sp' package.

Before this patch, the SP constans were in vcpe model.
As model must remain template independent, constant should not be there.

This patch moves VCPETemplate.java (defining constants) to org/opennaas/extensions/vcpe/manager/templates/sp/
Rename SP template related classes so they include "SP".

This patch renames VCPETemplate.java and VCPETemplateSuggestor.java
to SPTemplateConstants.java and SPTemplateSuggestor.java respectively.

This change is made to help identifying template dependent classes.
Create VCPENetworkModel with the structure required for MP-vCPE Template.

This patch adds MPTemplateModelBuilder.java which is able to create a VCPENetworkModel with the structure required for MP-vCPE Template.

MP-vCPE template requires the use of a new class in the model IPNetworkDomain.
This class will store some attributes related to addressing (yet to be decided).
Merge branch 'develop' into feature/mp-vcpe-element-definition

Conflicts:
	clients/opennaas-gui-vcpe/src/main/java/org/opennaas/gui/vcpe/utils/model/VCPEBeanUtils.java

Both modified VCPEBeanUtils.java.
Conflicts solved by manually merging.
Merge pull request #513 from isartcanyameres/feature/mp-vcpe-element-definition

Feature/mp vcpe element definition