EventStore streaming improvements

[marein]

• Dispatch events via PSR-14 event dispatcher so that clients can hook into the lifecycle.
• Move debug logs to an event listener instead of using a decorator.
• Add a listener that resets services to avoid possible memory leaks.
• Encapsulate EventStore dispatcher code in a single class to improve readability.
• Improve UI by adding boxes and colors.
• Use a comma-separated list to specify which subscribers to use.
• Rename argument -w to -p to specify how many events are processed in parallel. Default is now set to 1.

Related adjustments for ForkPool:

• Use stream_select before reading from a channel to get immediate signal handling.
• Make each fork a session leader so that only the main process receives SIGINT when the command is interrupted in the terminal.