Consider the process for loading Lexical translations post Payload 3 upgrade

[thompsonsj]

See #164.

At present, it seems to be working well. Content is loaded as Slate and then converted using Payload's Slate to Lexical migration support. This was implemented out of necessity - there was a lot of struggle trying to load translations into Lexical directly!

However, this approach has limitations, and will likely only go so far - i.e. can only support basic content.

Is there a better way to do this with Payload 3?

Reference: #164