[C++] Support reading delta dictionaries in IPC streams

[asfimport]

This JIRA covers the read path for delta dictionaries. The write path is a bit more of a can of worms (since the deltas must be computed)

Reporter: Wes McKinney / @wesm

Related issues:

• [C++] ensure C++ implementation meets clarified dictionary spec (is superceded by)
• [C++] Move "dictionary" member from DictionaryType to ArrayData to allow for changing dictionaries between Array chunks (depends upon)

_{Note: This issue was originally created as ARROW-5279. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Don't think I can get to this for 0.14

[asfimport]

Antoine Pitrou / @pitrou:
This seems addressed by ARROW-7285.