Keep files readable when they use future logical types

[kevinjqliu]

This is part of the effort to ensure that new logical types are forward compatible (See apache/parquet-format#599)

Description

This makes parquet-java more tolerant of Parquet files written by newer implementations.

A newer writer may use a logical type that this version of parquet-java does not know about yet. The file can still have a perfectly valid physical column type, but today the reader fails while trying to interpret the unknown logical-type metadata.

The fix is to handle that case in ParquetMetadataConverter, where file metadata is translated into parquet-java schema annotations. If the logical type cannot be understood, the converter now leaves the column as its physical type instead of failing. That is the right behavior for forward compatibility: readers should preserve the data they can understand, and only apply logical annotations when they are known.

This also keeps the existing fallback behavior intact for files that include older converted_type metadata.

Tests

Added tests cover reading an unknown logical type both with and without a converted_type fallback.

[kevinjqliu]

Added a test using the parquet-testing artifact

unknown-logical-type.parquet
A file containing a column annotated with a LogicalType whose identifier has been set to an abitrary high value to check the behaviour of an old reader reading a file written by a new writer containing an unsupported type (see related issue).

-- from https://github.com/apache/parquet-testing/blob/master/data/README.md

ref: https://github.com/apache/parquet-testing/blob/master/data/unknown-logical-type.parquet