Improved alternatives list for #152, improvements for #101

* Alternatives list now contains registry indicator
* Edit alternative now contains action definition
* Keep status quo is now a predefined alternative
* Add alternative, keep status quo UI is now unified with registry alternatives
Removed init(plan) call from save, ref #149

* Removed the init(plan) call introduced in 609ab8d92d5da0034202ef85b181909d3aea4371 as this resets a lot of view parameters