Updated the script to support installing multiple Flarum extensions in one command.

[DoyoDia]

While migrating from a direct installation to your Docker version, I faced several issues, one being the incorrect migration of plugins. I resolved this by reinstalling them, requiring a script to install over seventy plugins. Recently, I discovered that modifying the script could expedite this process. Therefore, I had ChatGPT modify the code to support processing multiple package names simultaneously.

[DoyoDia]

I'm relatively new to Git and have done my best to follow the online guide in this pull request. However, if there are any inaccuracies or issues, please feel free to make adjustments or guide me on how to correct them. I appreciate your understanding and help!