Define router model classes for Link Aggregation.
Update router model classes related to link aggregation.
Parser for link aggregation related configuration.

The parser does following things:
- looks for interfaces with aggregated-ether-options tag and creates AggregatedLogicalPorts representing them.
- looks for aggregated-ether-options and parses some of them in AggregatedOptions beans. (only minimum-links, link-speed and lacp active are parsed.)
- looks for interfaces with ieee-802.3ad tag and relates them with the aggregator mentioned above.
- populates the model with created classes.
Remove AggregatedLogicalPorts before parsing.

Avoiding AggregatedLogicalPorts duplication when GetConfigurationAction is called several times with the same model.
Test for link aggregation parser.
Merge pull request #889 from isartcanyameres/feature/link-aggr-capab-junos-parser

Feature/link aggr capab junos parser