[Go] Add Reset method to various components and clean up comments #24141

The reset method allow the data structures to be re-used so they don't have to be allocated over and over again.

Reporter: Richard / @richardartoul
Assignee: Richard / @richardartoul

PRs and other links:

• GitHub Pull Request #6430

_{Note: This issue was originally created as ARROW-7921. Please see the migration documentation for further details.}