chore: make services run more deterministically

[hsxfjames]

• The original approach to run the start script is to run it under nohup and place it in background, redirecting its stdout and stderr somewhere, as well as the nginx, php-fpm and redis-server services. But this way we may unfortunately lost all the useful information while starting up the services, like a config error causing it fail to start, or a permission problem.
• In this commit, I removed all the nohup commands, & operators, and also the output redirection. Were there any problem during service startup, we might easily find it. It helps us to reduce meaningless debugging time and concentrate on developement.
• The reason why we can do this is that all these services are daemonisable, they can be run in background via corresponding configs.
• This commit also slightly improves php-fpm performance by substituting http listening with socket listening, b/c the nginx and php-fpm services are run in the same container, they can communicate directly avoiding networking costs.

[zgq354]

I believe we're working towards implementing a superior LNMP dev environment, not just limited to Flarum. 😯