Settings: add logpersist selection (actions)

- Only add logpersist menu if debuggable.
- Only enable logpersist menu if Logging is On.
- Add selection for Off, All and All minus radio.
- Pop up warning box that persistent storage is to be cleared when
  selecting Off (but not if turned off by Logging Size Off or
  Disabling Debugger Options).

Bug: 28936216
Change-Id: Ic0a58abdcd6ca41069efb818d1dcef4e3927d2de