0.4.0: General improvements and tidying

What's Changed

• Fix shutdown by @abbiemery in #335
• Extract handler methods to ABC by @joeshannon in #342
• Add try except to messaging connection by @abbiemery in #345
• Adapt to Black 24 by @joeshannon in #358
• Run BlueskyContext and Worker in subprocess by @joeshannon in #343
• Remove reference to deleted devcontainer documentation by @callumforrester in #373
• Remove parameter caching inside task class by @callumforrester in #370
• Enable getting Stomp authentication credentials from the environment by @DiamondJoseph in #374
• Revamp architecture diagram and add logo by @callumforrester in #344

Full Changelog: 0.3.15...0.4.0