Touch ID button request

this crude build of testing Touch ID. no warranties guarantees etc...only for test purposes with non-production keepass databases etc...use at your own risk.

Notes:

-Constraints for the Touch ID are not quite right. This will need to get addressed to merge into core code

-so users should be able to request Touch ID again or each time as long as they don't select the options for "Always Allow" --keychain users essentially is the same effect if you save it in your keychain it will ask for you keychain password each time you lock it. If select "Always Allow" your database will always just unlock as long as your login keychain is unlocked.