"Hide from algorithmic recommendations" preference

[Tamschi]

This is stored as app.bsky.actor.contentVisibilityDeclaration["self"]#hideFromAlgorithmicRecommendations (a boolean):
https://lexicon.garden/lexicon/did:plc:4v4y5r3lwsbtmsxhile2ljac/app.bsky.actor.contentVisibilityDeclaration

On Bluesky, this setting is presented like this:

This may also be a step towards resolving the following issue:

• AP: interpret unlisted (aka quiet public) as public? #1036