Module package management

[schrnz]

In the context of Project-ARTist/meta#3, we will have different module packages instead of one compiler version that has them hard-coded. So we need to manage those module packages and keep track of them.

Assuming we have a fixed package format, we need logic to

• [x] load modules from the file system and parse them (extract meta information & files)
• [x] persist them in a database
• [x] remove them from the database
• [ ] update them from the file system

This issue only focuses on the handling logic, not the corresponding UI.

[schrnz]

Merged (all points but "updated from file system")