Check if dependencies are up-to-date using hash or batching

[jribbink]

Issue To Be Solved

Currently, flow deps install naiively downloads new copies of all contracts. This impacts performance and risks rate limiting

(Optional): Suggest A Solution

We can improve this by doing a batched hash check against current contract code on-chain to see what is up-to-date.

We should also look into whether we can do batched downloads of dependencies. This depends on what the limits are for script results which will need to be investigated.