Missing documentation about ParameterType_Bool

Description

ParameterType_Bool is not documented. Also clarify if ParameterType_Empty is deprecated, and what it means for users of the ApplicationEngine API.

Steps to reproduce

https://www.orfeo-toolbox.org/packages/nightly/latest/SoftwareGuide-6.6/SoftwareGuidech30.html#x61-41000030.2.4

Configuration information

all