[Rust][DataFusion] Add count_distinct to dataframe API

[asfimport]

Reporter: Daniël Heres / @Dandandan
Assignee: Daniël Heres / @Dandandan

PRs and other links:

• GitHub Pull Request #9028

_{Note: This issue was originally created as ARROW-11046. Please see the migration documentation for further details.}

[asfimport]

Andy Grove / @andygrove:
Issue resolved by pull request 9028
#9028