Store more nuanced info on deceased parents

Historically, the agp website includes only one "deceased_parent" field, which is represented as a checkbox. If this box is checked, the user only has to input one parent name, whereas if it is not checked, they have to input two. If the box is checked, the assumption is that the parent whose name is input is the living one.

I don't know whether the agp website PREVENTS the user from entering a second parent name if the checkbox IS checked. If not, it could be confusing to know which of the two parents listed is the dead one :-/

Also, AFAIK the website doesn't support the case of orphans in a very clear way as there's no way to indicate that both parents are dead; the assumption in this case is that the checkbox would be checked and that the "Parent 1 name" would be the name of the legal guardian who was giving consent in the name of the child, but this isn't explicitly laid out.

Weirdly, in the current ag database, the deceased_parent field is stored as a varchar(10) rather than a boolean ... in the existing test agp db, it is holding a terrifying mixture of "No", "false", "true", "yes" (note lack of capitalization), and null.

These are probably pretty rare cases, but if we have bandwidth, it would be worth improving their handling--especially if/when AGP plans to extend into geographical or clinical populations where these cases are more common.