[Rust] PrimitiveArray<T> should support comparison operators

[asfimport]

PrimitiveArray should support comparison operators such as <, <=, >, >=, ==, != so that two arrays (of the same type) can be compared and produce a PrimitiveArray containing the result.

Reporter: Andy Grove / @andygrove
Assignee: Andy Grove / @andygrove

Related issues:

• [Rust] PrimitiveArray should support simple math operations (is a child of)

_{Note: This issue was originally created as ARROW-3881. Please see the migration documentation for further details.}

[asfimport]

Andy Grove / @andygrove:
I've implemented this as part of the PR for ARROW-3880 since the code is so closely related

[asfimport]

Andy Grove / @andygrove:
This was handled in https://github.com/apache/arrow/pull/3033 along with ARROW-3880