[FEA] Java bindings for DECIMAL32 and DECIMAL64 types

[jlowe]

Is your feature request related to a problem? Please describe.
Spark has a DecimalType which is a fixed-point type with a configurable precision and scale. The RAPIDS Accelerator for Apache Spark would like to accelerate DataFrame operations using this Spark type which requires fixed-point type support in libcudf.

Describe the solution you'd like
cudf's Java bindings expose new column data types for the libcudf DECIMAL32 and DECIMAL64 types added in #5704 and updates the bindings of any associated methods to deal with the new type. While this won't cover the full gamut of Spark's DecimalType it would allow the plugin to accelerate queries where a mapping to a libcudf fixed-point type is possible.

[github-actions]

This issue has been marked rotten due to no recent activity in the past 90d. Please close this issue if no further response or action is needed. Otherwise, please respond with a comment indicating any updates or changes to the original issue and/or confirm this issue still needs to be addressed.

[jlowe]

Implemented in #6514 and others.