[C++] Add cast "metafunction" to FunctionRegistry that addresses dispatching to appropriate type-specific CastFunction

[asfimport]

By setting the output type in CastOptions, we can write

call_function("cast", [arg], cast_options)

This simplifies use of casting for binding developers. This mimics the standard SQL

CAST(expr AS target_type)

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

Related issues:

• [C++] C++ array kernels framework and execution buildout (umbrella issue) (is a child of)

PRs and other links:

• GitHub Pull Request #7258

_{Note: This issue was originally created as ARROW-8918. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 7258
#7258