Strenght phase : manually trigger and/or setup

You may have plenty reason to do a strenght phase whenever you want, so it would be nice to have the option to do so at any moment during a hypertrophy program.

Also, allow the user to determine the number of trainings with hypertrophy program before starting a strenght phase. So for those who prefer to do strenght training more often than hyperthrophy, that will be possible, or if the program is having issues with the count down, you may be able to adjust it manually.