@murgero (you probably know this but just writing it out for the wider audience)...
Cloudron was primarily made to install and manage pre-packaged apps. This meant that addons were defined by the package and we don't want end users to make difficult decisions as to what database to use and what caching backend to use. Lesser choices cover 90% of the use cases.
But over time, we saw a lot of demand about custom apps. And thus LAMP app and even allowing custom packages. And now we probably also need dynamic addons (ie. select which database post installation or just before installation). While this is doable, this moves Cloudron more and more into PaaS territory. My initial instinct is that it's fine to venture into this space and maybe cover 90% of the use cases but we have to think through it 🙂