add play index matchups vs batters for players

[double-dose-larry]

https://www.baseball-reference.com/play-index/batter_vs_pitcher.cgi?pitcher=degroja01

maybe combine with vs_pitchers into one function.

something like

Player("Emilio Pagan").vs("b")
Player("Tommy Pham").vs("p")

could possibly use the Player().pit_or_bat_default to infer the default, so the code could just be

Player("Austin Meadows").vs() # returns vs_pitchers dataframe

[double-dose-larry]

combined into the Player.vs() call.