Query Node: Allow moderation of posts with `PostStatusLocked` via metaprotocol

[Lezek123]

Query node should support moderation of posts with PostStatusLocked (posts that no longer exist in the runtime, but were deleted with hide flag set to false) through a new metaprotocol message sent via forum working group's worker_remark extrinsic.

The query node will have to:

• check whether the moderator that sent the remark has access to moderate the category that the post currently belong to in the database (post->thread->category). Note that you also need to recursively check category->parent, because if the moderator has access to the parent category, it should also be allowed to moderate posts under its child categories
• update post status to PostStatusModerated if the moderator is allowed to moderate the post

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