[FEA] Port cuIO to cudf::column types

[j-ieong]

Is your feature request related to a problem? Please describe.
This issue tracks the effort for moving cuIO (readers, writers, tests) to using the new column design and associated infrastructure.

Describe the solution you'd like
Currently, cuIO uses wrappers around the C-style gdf_column to aid in storing/accessing column metadata and allocating/deallocating memory. We should be able to get rid of the custom C++ wrappers and directly use the cudf::column and cudf::table.

Prerequisites:

• Require new column code cudf::column redesign #2207.
• Require string support [REVIEW] cudf strings column #2811
• Require different timestamp column types [REVIEW] Add cudf::column timestamp wrapper types #2918
• Require column name metadata in either column or table
• Detail how to hand-off to Cython / Python

Describe alternatives you've considered
We may or may not need some sort of temporary wrapper or custom column class still within cuIO to temporary hold column metadata that's format-specific, for delayed column creation to save memory or other usage. The returned columns will be cudf::column and cudf:;table though.

Additional context
See other porting efforts for libcudf.

[mjsamoht]

Moving to 0.12 for remaining tasks.

[mjsamoht]

Closing this issue. Remaining work will be tracked in #3521 and #3522.