feat(db-postgres): join field support relationships inside arrays

[r1tsuu]

PR to https://github.com/payloadcms/payload/pull/9773 Not only implements join field support relationships inside arrays in Postgres / SQLite, but also:

• Significantly improves traverseFields and the 'join' case with a raw query injection pattern, right now it's internal but we could expose it at some point, for example for querying vectors.
• Fixes potential issues with not passed locale to traverseFields (it was undefined always)
• Adds an empty array fallback for joins with localized relationships

With the improve in traverseFields it should be also easy to add blocks support if we want.