Refactor LLDP management addresses and deprecate previous management address leafs

[earies]

• (M) release/models/lldp/openconfig-lldp-types.yang
  • Addition of management address related identities/typedef
• (M) release/models/lldp/openconfig-lldp.yang
  • Addition of new management address hierarchy to match IEEE 802.1ab-2016 definition
  • Deprecate flat singleton management-address leafs
  • Leverage OC types vs. previous IETF types

Change Scope

The previous definition of LLDP management addresses had the following design flaws

• Singular management address (IPv4 or IPv6)
• Only partial support of the Management Address TLV per IEEE 802.1AB-2016
• Non-configurable management-address selection
• Lack of support for conveying local management addresses

This change encompasses:

• A new list structure to accomodate multiple management addresses
• Expansion of the structure to support relevant Management Address TLV fields
• Support to convey local system management addresses
• Commencing deprecation of the previous 2 leafs representing a single management address
• Removal of IETF types in favor of OC types (keeping same underlying types)

While openconfig-lldp has been bumped to 1.0.0 due to the import/type changes from IETF -> OC, this change is mostly backwards compatible as we are slowly deprecating the previous management-address related leafs.

This change better aligns Management Address TLV support to the IEEE 802.1AB-2016 spec.

Platform Implementations

For configurable management address interface derivation:

• Juniper JUNOS/EVO: https://www.juniper.net/documentation/us/en/software/junos/multicast-l2/topics/task/layer-2-services-lldp-configuring.html
• Arista EOS: https://www.arista.com/en/um-eos/eos-link-layer-discovery-protocol#xx1149426

Remainder is for IEEE 802.1AB-2016 compliance