Fix CI/CD pipeline

Common - Tools - Descriptor:

• Implemented unload for dummy mode

PathComp component - Frontend:

• KDisjointPath: Corrected method get_link_from_endpoint
• KDisjointPath: Generalized get_reply method
• KDisjointPath: Corrected json_reply data strcture
• Updated unitary test objects
• Updated unitary test scenario load/unload
• Updated Dockerfile

Policy component:

• Add IETF_L2VPN enum in DeviceDriverEnum
• Minor code styling