eTB Manager

When changing the regimen, user may want to specify the start date (when a treatment regimen has already started).

1. If user doesn't enter the 'Start date', follows the current implementation.

2. If user enters a new 'start date', the system will do the following:

a. The start date must be equals or bigger than the start treatment date;
b. The initial regimen will be the current regimen and the current regimen will be the new one informed;
c. The system will store the start date of the new regimen. This date will be used in future changes of the regimen to check if the regimen is still the same or if it moved to an individualized one;