Lambda smart deploy with webpack changes

[remi00]

What it does?

• Adjust format of artifact paths to <prefix>/<stage>/<function_name>/<hash>

What else is important?

• It assumes that ZIP files created in the package step have deterministic hash - they don't change per each build, just when the actual content change. This is true assumption for pure serverless config and will be true for serverless-webpack config assuming this ticket will be resolved, which should be the case with this PR after suggested changes are applied
• This is just PoC, not to be merged yet. It will require lots of things to happen:
  • Rollback handling
  • Review of configuration that can affect the behavior
  • Tests updates
  • ... ❓

[remi00]

Officially raised updated version under serverless#9876