MD-SAL packages a lot of IETF models, some of which are needed downstream. Most notably ietf-netconf.yang is packaged in netconf.git and needed in tcpe-models.

Adopt IETF RFC models from netconf.git. While we are at it, update available models with:

1. RFC7317 ietf-system.yang

2. RFC7407 ietf-snmp.yang

3. RFC8572 Secure Zero Touch Provisioning

4. RFC8808 Factory Settings

5. RFC9144 NMDA Compare

6. RFC9179 YANG Geographic Locations

7. RFC9196 YANG Capabilities for Systems and Datastore Update Notifications