Refactor pool code to update block timestamp to when block is found

[ghost]

Nodejs-pool and Node-cryptonote-pool uses the time when the block template was created as the timestamp when sending jobs to miners and is not updated after some time passes. Pool code should be modified to adjust the timestamp to when the block is actually found. This would help reduce the number of delays in lwma-4 difficulty algorithm

[ghost]

Depending on pools/miners to report the correct timestamps is not an ideal solution, difficulty algorithm will switched out to something else.

[zawy12]

Pools and miners already have the ability to select the timestamp because they can have their own nodes who create the timestamp. It allows them to assign a more accurate timestamp like BTC et al instead of the incorrect timestamps they currently assign.