Could you point me to any open source projects/references you've used for your platform that showcases this plugin architecture? I'm a junior developer and I'd really like to learn and incorporate this in my projects.
Sure, here you go. That'll get you started. We didn't adopt any of that or a specific solution/library/way, but they were good resources to think about the matter.
That's from our internal wiki, and "Plugin Architecture" was the first entry in that, just to tell you about how important it was.
Also, given that you describe yourself as a "junior developer", here's a reply to an Ask HN about "How to become a senior developer".
Description: Doug Hellmann talks about Stevedore, a library that provides classes for implementing common patterns for using dynamically loaded extensions
Thanks a lot for taking the time to list these resources (in this post as well as in the other Ask HN post)! This is really helpful for beginners like me. :)