Add dev train

[Ornias1993]

Is your feature request related to a problem? Please describe.
While working on new features, I noticed it might sometimes be prefered to test new features in concert with current Apps for a while. These are often working Apps, that just might some TLC on polishing the GUI and similair things.

However: currently that would mean either merging them into staging or incubator, both which they are not:
They are no stable App (obviously) but they are also no incubator chart (they are in development, are not expected to be fully stable either)

Describe the solution you'd like
Add a "dev" train, for Apps that are in active development.

[truecharts-admin]

This issue is locked to prevent necro-posting on closed issues. Please create a new issue or contact staff on discord of the problem persists