[DO-NOT-MERGE][PYTHON] Simple Pythonic catalog reference

[HyukjinKwon]

What changes were proposed in this pull request?

>>> from pyspark.sql import ref
>>> spark.range(10).write.saveAsTable(ref.my_table)

>>> spark.table(ref.my_table)
DataFrame[id: bigint]

>>> spark.table(ref.default.my_table)
DataFrame[id: bigint]

>>> spark.sql(f"SELECT * from {ref.my_table}").show()
+---+
| id|
+---+
|  4|
|  0|
|  6|
...

Why are the changes needed?

TBD

Does this PR introduce any user-facing change?

TBD

How was this patch tested?

TBD

Was this patch authored or co-authored using generative AI tooling?

No.