NetSoft Hackfest extensions, gNMI Driver, gNMI L3NM Service Handler, multiple fixes

Common:

• Added .dockerignore file to accelerate builds
• Improved my_dpeloy.sh script example

Hackfest Material:

• Added ContainerLab experiment
• Updated and re-organized TFS descriptors

Manifests:

• Minor updates in manifest files and cleanup

Device component:

• Implemented gNMI Driver (configuration and monitoring)
• Minor cosmetic changes in OpenConfig Driver

Monitoring component:

• Added filter to monitor only enabled endpoints
• Minor bug-fixing
• Changed default sampling rate to 10 seconds

PathComp component - FrontEnd:

• Updated ComposeConfigRules to support /device/settings config rules
• Updated composiion of paths from EROs

Service component:

• Added L3NM Gnmi OpenConfig Service Handler

WebUI component:

• Added gNMI OpenConfig driver options
• Minor cosmetic changes