split has/wants, requires/improves into separate properties

[allysonlister]

The following are currently conflated, which was fine for the first version as it allowed our use cases to be built.
However, as people will want to use the opposing meanings in different circumstances, we should split them out with appropriate definitions.

http://purl.obolibrary.org/obo/T4FS_0000558 has/wants competency in
http://purl.obolibrary.org/obo/T4FS_0000559 has/wants knowledge about
http://purl.obolibrary.org/obo/T4FS_0000561 has/wants practical skill about
http://purl.obolibrary.org/obo/T4FS_0000556 requires/improves personal attribute