Move content class
What does this MR do?
This MR moves the content class into the new src/Modules structure.
Also, it sets up the internal loading via loadApp so it supports old as well as new module structure (in the vision to remove the code able to load old style as soon as it is ready)
How confident are you it won't break things if deployed?
tests seem okay, quite likely all codepaths are triggered.
Links to related issues
- added a test, or explain why one is not needed/possible...
- no unrelated changes
- asked someone for a code review
- joined #foodsharing-beta channel at https://slackin.yunity.org
- added an entry to CHANGELOG.md (description, merge request link, username(s))