Operator assumes stack creation if it doesn't exist

[elsesiy]

The current implementation always assumes that a stack that doesn't exist in the tracking git repo to be automatically created, see here.

This could be problematic as users might want to decouple the stack creation from the stack CR creation (often live in different repos). Stacks often require certain configs to be present and assume the default values as part of the created stack by the stack CR might not be desirable.