Return 'true' if post was edited and 'lastEdited' timestamp. Return edit history.

[brootle]

Update DeSo API.

/api/v0/get-posts-for-public-key should add IsEdited: true if post was edited and the timestamp when the post was edited last time.

/api/v0/get-single-post must return post edit history details or make another API call to get edit history details for the post.

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