Resolve "Notificatoins from Context are incomplete"

Closes #54 (closed)

Common - Message Broker - NATS:

• Improved subscriber error handling and logging
• Minor linting improvement

Common - Tests - MockMessageBroker:

• Removed unused TOPICS variable

Common - Tools - Context Queries:

• Updated method create_topology() to enable defining the topology name
• Implemented get_topology_details() method

Context Component:

• Moved generation of events to the database sub-module
• Improved API for notification publication and consumption
• Moved construction of gRPC reply objects to the database sub-module
• Moved generation of change notifications to database sub-modules
• Activated reversed relations in TopologyDeviceModel and TopologyLinkModel
• Extended Topology to notify changes on Context when Topology is modified or deleted
• Extended Device to notify changes on Topology and Context when Device is modified or deleted
• Extended Link to notify changes on Topology and Context when Link is modified or deleted
• Extended Link to report changes when Endpoints are added.
• Extended Service to notify changes on Context when Service is modified or deleted
• Extended Slice to notify changes on Context when Slice is modified or deleted
• Minor cosmetic improvements