Extract metadata about rosters from the questionnaire JSON as a data frame.
Value
Data frame with the following columns:
object_type. Character. Simplified object type. Value:roster.type. Character. SuSo-provided object type. Value:Group.condition_expressionhide_if_disabledis_flat_modeis_plain_modedisplay_modeenableddescriptionvarnameis_rostercustom_roster_titleroster_size_question_idroster_size_sourcepublic_keytitlefixed_roster_title_*fixed_roster_value_*