2.04.0:minrog:5 BA purge, Roman/Gallaway

Deleted a bunch of titles and history files that were BA only and
probably not Millenium+ compat.  Removed duplicate 00_tradeposts.txt,
added the gallaway culture to the north_germanic castles file, added
roman culture to the italian castles file.  Removed the latin
sub_culture from castles and retinues to account for cultural cities
integration.  Merged the retinue file into the main CK2+ file for easier
addition of cultures and less redundancy.  Note: Must remove reference
to the BA only pagan_economy triggered_modifier (in
0_better_armies.csv).