* Use common 'apply' backend for init and upgrades
* Move unit tests to new apply backend
* Only perform Terraform migrations if state exists in cwd (#2457)
* Rework skipPhases logic
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Signed-off-by: Daniel Weiße <dw@edgeless.systems>
Co-authored-by: Moritz Sanft <58110325+msanft@users.noreply.github.com>