🎛️ Consider adding harvest method to BaseStrategy

[dantop114]

A method to harvest a strategy would be desired. At the moment strategies are exposing methods to handle strategies positions. In case of multistep strategies this leads the harvester to fire multiple transactions to harvest a strategy. This is simply boring.

The only technical choice left is if harvest should accept configuration parameters in input. Take for example the BeetsStrategy: staking rewards for staking LP tokens on Beethoven can be used in two ways. How do you split those? Can this split decision be made on a harvest-by-harvest basis?

Having a signature for harvest like harvest(bytes memory payload) seems to be more flexible.
Having a signature for harvest like harvest() seems to be less flexible as the strategy needs more code to config the harvests and each harvest may need more than one tx (setting params, calling harvest).