- Added config flag ALLOW_EXPLICIT_ADD_DEVICE_TO_TOPOLOGY
- Added config flag ALLOW_EXPLICIT_ADD_LINK_TO_TOPOLOGY

- Extended MockServicerImpl_Context to add/remove topologies, services and slices to/from contexts

- Corrected return type in Topology methods

- Enabled explicit addition of devices and links to topologies

- Added config flag ALLOW_EXPLICIT_ADD_DEVICE_TO_TOPOLOGY
- Added config flag ALLOW_EXPLICIT_ADD_LINK_TO_TOPOLOGY
- Added logic to explicitly add devices and links to topologies

- Changed default values to False for config flags ALLOW_EXPLICIT_ADD_DEVICE_TO_TOPOLOGY and ALLOW_EXPLICIT_ADD_LINK_TO_TOPOLOGY

Merge branch 'feat/95-cttc-extend-context-component-to-explicitly-add-devices-and-links-to-particular-topologies' into 'develop'

Resolve "(CTTC) Extend Context component to explicitly add devices and links to particular topologies"

Closes #95

See merge request !180