[C++] Add function to concatenate like-typed arrays

[asfimport]

A la

Status arrow::Concatenate(const std::vector<std::shared_ptr<Array>>& arrays, MemoryPool* pool, std::shared_ptr<Array>* out)

Reporter: Wes McKinney / @wesm
Assignee: Ben Kietzman / @bkietz

PRs and other links:

• GitHub Pull Request #3746

_{Note: This issue was originally created as ARROW-549. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Marked for 0.4. We'll be needing this before too long

[asfimport]

Wes McKinney / @wesm:
This will be useful soon enough in arrow::compute

[asfimport]

Wes McKinney / @wesm:
I'm moving this to 0.14 so we aren't stressing about getting the patch merged for 0.13, since we aren't blocking on this feature for anything yet

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 3746
#3746