Implement create/remove in LinkAggregationcapability

They delegate to an action.
CreateAggregatedInterface implementation in junos driver.

CreateAggregatedInterfaceAction is responsible for configuring given AggregatedLogicalPort.
It uses two velocity templates:
- CREATION_TEMPLATE for configuring the aggregated interface
- ADD_TO_AGGREGATED_TEMPLATE for configuring each interface that is part of the aggregation.

CreateAggregatedInterfaceAction will fail if it is given an AggregatedLogicalPort whose name is already used by an existing aggregated interface in the junos config.
In particular, it is worth notice that launching CreateAggregatedInterface twice with same parameter will cause the second action to fail.
RemoveAggregatedInterface implementation in junos driver.

RemoveAggregatedInterfaceAction is responsible for removing the interface.
This action makes use of two velocity templates:
- DELETION_TEMPLATE which deletes the aggregated interface from the device configuration.
- REMOVE_FROM_AGGREGATED_TEMPLATE which deletes the association between existing interfaces and the removed aggregated one.

RemoveAggregatedInterfaceAction will fail if there is no AggregatedInterface with given name in the model.
This requirement is related to the action imlpementation, not capability defined.
There is need to retrieve the names of interfaces given aggregation includes, in order to remove an association in the junos configuration.

Above requirement limitates the usage of this action. Queue must be executed between a create and a remove. Otherwise remove will fail.
Merge branch 'develop' into feature/link-aggr-capab-create-remove-impl

Conflicts:
	extensions/bundles/router.actionsets.junos/pom.xml

Conflict solved manually. Both dependencies included.
Add comment regarding units not allowed in aggregated links.

The user is forced to delete subinterfaces in an interface
before being able to add it as part of an aggregated one.
Merge pull request #897 from isartcanyameres/feature/link-aggr-capab-create-remove-impl

Implementation of LinkAggregationCapability.createAggregatedInterface(AggregatedInterface aggregatedInterface) and LinkAggregationCapability.removeAggregatedInterface(String aggregatedInterfaceId).
Both methods delegate to an action each.

Such actions have been created in org.opennaas.extensions.router.actionsets.junos, and are part of LinkAggregationActionSet.

    CreateAggregatedInterfaceAction
    RemoveAggregatedInterfaceAction

WARNING: These actions have some limitations the user must be aware of:

    CreateAggregatedInterfaceAction requires interfaces to be aggregated include NO subinterfaces. User must delete existing subinterfaces before trying to use an interface in an aggregation.
    RemoveAggregatedInterfaceAction requires given aggregatedInterfaceId is in the model. User must execute the queue between a creation and a removal, or the removal will fail.

This patch fixes following issues:
http://jira.i2cat.net:8080/browse/OPENNAAS-1332
http://jira.i2cat.net:8080/browse/OPENNAAS-1333
http://jira.i2cat.net:8080/browse/OPENNAAS-1337
http://jira.i2cat.net:8080/browse/OPENNAAS-1338