pwpolicy: Fix new bool checks for IPA prior to 4.9.10

With 4.9.10, the value of bools have been changed from "TRUE" and
"FALSE" to real bool values.

With IPA < 4.9.10 the new bool checks distcheck and usercheck failed
the tests for enabling the checks with a "already enabled" error.

A new version check altogether with providing the ansible module for
gen_args has been added. The values True and False are now transformed
into "TRUE" and "FALSE" for IPA < 4.9.10.

The function bool_param has been renamed to bool_or_empty_param to match
the int_or_empty_param and to have a more explaining name.