Temp target duration fix

[kylmcw]

FIxed the temp target duration to be more dynamic when passing any number not null. Refactored messages to be more consistent when addressing user for temp targets. Renamed references to "Temp Target" to be more consistent from "Temp Preset" fixed OiAPS references in a few classes to Open-iAPS

Steps to reproduce:

• Create and set temp target as preset
• Run temp target from pre programmed shortcut in Shortcuts

Evidence of fix:

[kylmcw]

Suggestion: We could make the function public, move it to a utility function and apply it in places where "min" or similar is hard coded

[dnzxy]

I have no experience with iOS shortcuts, so I‘ll omit doing a review. Your changes look reasonable and limited, so sensible.

[bjornoleh]

Thanks! Please remember to create the PR to dev as well when this is tested in alpha, as we do not plan on merging alpha into dev.