[C++] Add "TypeResolver" class interface to replace current OutputType::Resolver pattern

[asfimport]

Like the TypeMatcher for extensible input type checking, TypeResolver will allow more flexibility with respect to the output type resolution rule. Currently the resolver function is defined as

using Resolver =
      std::function<Result<ValueDescr>(KernelContext*, const std::vector<ValueDescr>&)>;

By changing to a TypeResolver interface with a virtual Resolve function, we also can provide for better human-readability when printing kernel signatures (by having TypeResolver::ToString) and permitting TypeResolvers to be compared

Reporter: Wes McKinney / @wesm

Related issues:

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

_{Note: This issue was originally created as ARROW-8921. Please see the migration documentation for further details.}