Remove url resolvers as server actions

[mobeigi]

The async url resolvers are current server actions.

This is because the link node type ReactNode resolver relies on these functions for internal links.
The resolvers are server side because they need to fetch a doc to populate doc relationships that might not be there (due to Payload using depth 0 by default).

Finally, CommentSection, a client side component uses serializeLexical which is fully client side except for the link node which is the only async server side resolver.

Some solution ideas:

• Payload: If Payload allowed us to populate the url field for internal links at edit time. This way the JSON section for links would be properly self-contained (as is the case for external links). This would allow us to keep link node fully client side solving the problem. However, one issue with this approach is the persisted url would need to be invalidated / updated if the url setter function logic changes.
• Avoid calling serializeLexical in client-side components (currently only CommentSection), make the resolution happen at a higher level and pass it down to client side components. Basically, treat serializeLexical as fully server-side only.

[mobeigi]

Discussion on Payload Discord help thread:
https://discord.com/channels/967097582721572934/1300047914566942741/1300047914566942741