possible improvement for drago price source

[gabririgo]

currently the price is updated and stored directly in the drago contract. This is quite efficient, but there is a possible improvement:

retrieve buy price and sell price from the registry or a price module.

the price could be updated by the owner of the fund or by the nav evaluation module.

this will allow later on to add the nav evaluation module and be ready for being upgraded when the module works fine.

This would also potentially save some space in the drago contracts as some of the logic would be moved to the module

[gabririgo]

The rationale of leaving the price out of the registry is that even funds that have been unregistered must be able to query their price, as investors need to get out.

So the only possible solution is to create a price module, which will eventually become the price feed module