Menu link content entities that point to nodes are not deployable

Problem/Motivation

Menu link content entities when normalized contain references to node serial IDs (nid) and not UUIDs, this means they cannot be deployed.
Snippet:

...
  ],"link": [
        {"uri": "entity:node\/2","title": null,"options": []
        }
    ],
...

Proposed resolution

We have several options:

1. #2315773: Create a menu link field type/widget/formatter
2. #2353611: Make it possible to link to an entity by UUID
3. Add a normalizer that swaps NID for UUID on normalize and swaps it back on denormalize

Remaining tasks

Decide on the best approach

User interface changes

None

API changes

Depends on the approach

Data model changes

Depends on the approach