Server analysis could use cloud analysis in the opening

[Yery]

Currently, when a server analysis is requested, all moves are analysed, including the opening. The opening however, could be queried from the cloud, which has a much deeper analysis. So the suggestion is, whenever a (deeper) cloudanalysis is available, to use that one, instead of a (redundant) shallower reanalysis. This would save time, and should save a bit on the electricity bill too!

[ornicar]

What do you think @niklasf?

ATM cloud analysis doesn't have an HTTP API, but it could be added.

[niklasf]

Architecturally it seems a bit wierd to let fishnet query an HTTP API. Instead lila could add information from its own database.

[ornicar]

It also seems weird to send analysis to fishnet. Also it's hard to just tell fishnet "don't analyse these positions, I got them already" because by the time fishnet completes the analysis, the cloud eval entry could be gone (they expire if unused). Actually nevermind that, using a cloud eval entry like that could also prevent expiration.

So lichess could add to the fishnet payload a list of plies that need not be analyzed.

[ornicar]

For now I'll just monitor how many positions are affected.

[ornicar]

Turned out this change results in 13% less work for the same result, so it was deployed