Rewrite and complete the manpage's env var list
Rewrite and complete the manpage's env var list

This includes everything I could find with an `ack 'ENV<' src/` command.
Descriptions have been expanded on, expected datatypes are shown, and items are
now broken up into categories.

paultcochrane/rakudo,ugexe/rakudo,salortiz/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,ugexe/rakudo,jonathanstowe/rakudo,rakudo/rakudo,ugexe/rakudo,zostay/rakudo,awwaiid/rakudo,sjn/rakudo,dankogai/rakudo,tbrowder/rakudo,ab5tract/rakudo,rakudo/rakudo,lucasbuchala/rakudo,dankogai/rakudo,tbrowder/rakudo,ab5tract/rakudo,b2gills/rakudo,samcv/rakudo,rakudo/rakudo,Gnouc/rakudo,tbrowder/rakudo,awwaiid/rakudo,labster/rakudo,softmoth/rakudo,tbrowder/rakudo,Gnouc/rakudo,b2gills/rakudo,rakudo/rakudo,tbrowder/rakudo,tbrowder/rakudo,nbrown/rakudo,usev6/rakudo,labster/rakudo,MasterDuke17/rakudo,softmoth/rakudo,tony-o/rakudo,ab5tract/rakudo,ab5tract/rakudo,tony-o/rakudo,awwaiid/rakudo,dankogai/rakudo,azawawi/rakudo,Gnouc/rakudo,zostay/rakudo,LLFourn/rakudo,softmoth/rakudo,raydiak/rakudo,rakudo/rakudo,nbrown/rakudo,sjn/rakudo,paultcochrane/rakudo,nbrown/rakudo,paultcochrane/rakudo,tony-o/rakudo,samcv/rakudo,awwaiid/rakudo,usev6/rakudo,labster/rakudo,ugexe/rakudo,labster/rakudo,labster/rakudo,rakudo/rakudo,lucasbuchala/rakudo,azawawi/rakudo,jonathanstowe/rakudo,azawawi/rakudo,LLFourn/rakudo,dankogai/rakudo,LLFourn/rakudo,azawawi/rakudo,jonathanstowe/rakudo,paultcochrane/rakudo,salortiz/rakudo,MasterDuke17/rakudo,usev6/rakudo,ab5tract/rakudo,azawawi/rakudo,softmoth/rakudo,nbrown/rakudo,nbrown/rakudo,samcv/rakudo,LLFourn/rakudo,softmoth/rakudo,usev6/rakudo,tony-o/rakudo,dankogai/rakudo,salortiz/rakudo,usev6/rakudo,tony-o/rakudo,nbrown/rakudo,salortiz/rakudo,b2gills/rakudo,zostay/rakudo,salortiz/rakudo,paultcochrane/rakudo,tony-o/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,labster/rakudo,LLFourn/rakudo,MasterDuke17/rakudo,raydiak/rakudo,lucasbuchala/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,Gnouc/rakudo,zostay/rakudo,b2gills/rakudo,raydiak/rakudo,samcv/rakudo,jonathanstowe/rakudo,raydiak/rakudo,samcv/rakudo,b2gills/rakudo,awwaiid/rakudo,sjn/rakudo,ugexe/rakudo,jonathanstowe/rakudo,sjn/rakudo,salortiz/rakudo,sjn/rakudo,Gnouc/rakudo