Remove `CsvParser.enable()`/`.disable()`/`.configure()` (reduce mutability)

[cowtowncoder]

Looks like we forgot to remove/reduce mutability of CsvParser by leaving 3 methods in:

• public JsonParser enable(CsvReadFeature f)
• public JsonParser disable(CsvReadFeature f)
• public JsonParser configure(CsvReadFeature f, boolean state)

this is in oversight that should be rectified, even if it is technically incompatible API change b/w 3.0 and 3.1.
Since 3.1.0 is intended to be the first LTS for 3.x this is doable now, but not after 3.1.