Add NULL type to Bring Parquet logical types to par with Arrow

[asfimport]

Missing:

• Null
• Interval types
• Union
• half precision float

Reporter: Julien Le Dem / @julienledem
Assignee: Julien Le Dem / @julienledem

Related issues:

• Add INTERVAL_YEAR_MONTH and INTERVAL_DAY_TIME types (is blocked by)
• Add Union Logical type (is blocked by)
• [Format] HALF precision FLOAT Logical type (relates to)

PRs and other links:

• PR

_{Note: This issue was originally created as PARQUET-757. Please see the migration documentation for further details.}

[asfimport]

Julien Le Dem / @julienledem:
PR: #45

[asfimport]

Julien Le Dem / @julienledem:
Those differences came up in apache/parquet-java#381

[asfimport]

Julien Le Dem / @julienledem:
Issue resolved by pull request 45
#45