Support running parsers XOR checks separately

[gwerbin]

I want to assume that the output of my parser passes all checks (for use at runtime when loading data from an external source), to avoid running a lot of expensive and unnecessary checks at runtime. And in other situations, I want to be able to run all checks (either to validate input or during my test suite) but not run the parsers, assuming that the input data is already parsed.

As far as I can tell, that's not currently possible with Pandera. I would have to define 2 separate schemas, one with all my parsers and another with all my checks, which is verbose and error-prone (or requires a helper function to introspect and generate both from the same base schema).

I propose two new interfaces for this purpose: a .parse method which only runs parsers but not checks, and a .check method which only runs checks but not parsers.

The types would look something like this:

class DataFrameModel:
    def parse(self, df: DataFrame[Any], **config_kwargs: Any) -> DataFrame[Self]: ...
    def check(self, df: DataFrame[Self], **config_kwargs: Any) -> bool: ...

(The config_kwargs are from my other feature request here: #1837)