Improved OpenConfig Driver and Service Handler

See merge request !69

- Corrected processing of POST/DELETE messages
- Added test script

- updated log level to debug

- Added logic to ignore mgmt-related links
- Improved composition of subservice config rules
- Cleaned up Constants
- Updated sub-service computation logic

- Added logs to investigate issue (POST seems not to work)

- Added helprt method to get manager for devices

- Corrected Device request composition

- Corrected resource parsing in SetConfig and DeleteConfig

- Added bearers for OFC'23

- Added logic to keep order of link endpoints

- Added logic to retrieve sub-devices and its endpoints from remote controllers
- Added logic to retrieve remote links connecting sub-devices
- Added logic to handle device managers, i.e., controllers

- Added logic to retrieve configured services

- Added logic to retrieve configured services

- Added DebugAPI client used to acquire remote controller topology info
- Extended skeleton and preliminary implemented driver methods
- Extended WIM connector with a method to get a specific service

- Updated child deploy script to prevent re-building images after parent
- Updated descriptor files

- Improved filter to select service handler
- Disabled configuration of devices when there is nothing to configure
- Corrected TAPI Service Handler to use endpoint uuids instead of names
- Extended filters for selecting MicroWave Service Handler
- First implementation of L2NM IETF L2VPN Service Handler
- Extended service handler selector to be aware of devices managed by a controller
- Minor cosmetic changes

- Added Endpoint Name in Link, Service and Slice

- Renamed folder
- Improved error reporting

- Adjusted max number of endpoints per device
- Adjusted max number of parallel edges between nodes

- Fixed L2NM service generation

Partial update of Scenario 2

See merge request !67

- Updated deploy_specs

- Added missing device topology icons
- Added stylink to mgmt links in topology plot

- Added missing device types

Revision of OpenConfigDriver

See merge request !37

- Restored LoadGen default parameters

- Updated Netconf/OpenConfig log messages

- Updated Netconf/OpenConfig descriptor files
- Normalized variable names in OpenConfigDriver
- Minor code cleanup

- Reduced log levels to INFO
- Generalized paths
- Minor code and comment cleanup