feat: add s3 support, and create key if not exist

[IronCore864]

Description

Building on top of @algobot76's work:

• refactor to enable s3 backend;
• add a feature that when first using the s3 backend and the key doesn't exist, create the key automatically.

Docs update is in another PR: #548.

Related Issues

Closes #485, #378.

New Behavior (screenshots if needed)

config:

state:
  backend: s3
  options:
    bucket: devstream-test-remote-state
    region: ap-southeast-1
    key: devstream.state

Test