DataStore2/RapidDbic: Refined more configs + sane default vals

Pulled more config settings out of the RapidDbic-specific 'TableBase'
AppGrid class and moved them into lower API layers. Also added cascading
default values based on eachother, so 'toggle_edit_cells_init_off'
default value changes according to 'use_add_form' which (in the
TableBase) defaults according to the persist_immediately setting of the
'create' action. This allows for less required config options for
RapidDbic grid_params