Create a method to peek at the Catalog

This method's purpose is inspection. It should allow peeking at the catalog columns, their datatypes, and maybe some statistics stored in the parquet metadata (e.g. min, max values for each column). This method is key and should be at the start of each workflow. The goal is for users to perform the inspection to know more about the contents of the catalog and then go for a more informed use of `read_hats`.