Simplify DBIHacks signatures
The cross-polination of $attrs and various subparts is becoming a nightmare
to maintain. Straighten up most ::DBIHacks to pass stuff around as a single
$attrs bag (no functional changes, this is a temp-stage cleanup)
The idea is to prepare for an rsattrs object (later on all we will need to
do is replace the hash-grabs with methods, but this requires much more
thought and design, small steps)
Affected signatures in :DBIHacks:
_prune_unused_joins()
_resolve_aliastypes_from_select_args()
_adjust_select_args_for_complex_prefetch()
_extract_fixed_condition_columns()
Not touching to facilitate easier DQ merge (TODO in a sense):
_order_by_is_stable()
_main_source_order_by_portion_is_stable()