fix!: Remove deprecated ArgActions

[epage]

This required changing the default

• flags: SetTrue
• positionals with multiple values: Append
  • So pos1 pos2 --flag pos3 doesn't cause pos3 to overwrite pos1 post2 but appends to it
• all else: Set

To get the defaulted actions working properly, we had to move the defaulting code into Arg which required removing the non-accessible "NoAuto` settings.