[C++][Compute] Add decimal support to round functions

[asfimport]

Need to add Decimal support to the rounding compute functions. The PR for adding round compute functions (ARROW-12744) only includes basic arithmetic types (unsigned/signed int and floating-point).

Reporter: Eduardo Ponce / @edponce
Assignee: David Li / @lidavidm

Related issues:

• [C++][Compute] Add rounding kernel (depends upon)

PRs and other links:

• GitHub Pull Request #11323

_{Note: This issue was originally created as ARROW-13975. Please see the migration documentation for further details.}

[asfimport]

Yibo Cai / @cyb70289:
Issue resolved by pull request 11323
#11323