Generate catalog schema for joining/crossmatching

[camposandro]

We currently infer the schema for catalogs that result from joining and crossmatching operations. For that we provide the following helper method with the resulting Dask DataFrame's meta. While Pandas does a good job getting the schema right, we should generate it manually to minimize the risk of introducing an incorrect schema. Relates to #383.

lsdb/src/lsdb/io/schema.py

Lines 7 to 17 in efdd685

	def get_arrow_schema(ddf: dd.DataFrame) -> pa.Schema:
	"""Constructs the pyarrow schema from the meta of a Dask DataFrame.
	Args:
	ddf (dd.DataFrame): A Dask DataFrame.
	Returns:
	The arrow schema for the provided Dask DataFrame.
	"""
	# pylint: disable=protected-access
	return pa.Schema.from_pandas(ddf._meta)