[R] Implement TrimOptions

[asfimport]

Implement TrimOptions for all of:

utf8_trim_doc
utf8_ltrim_doc
utf8_rtrim_doc
ascii_trim_doc
ascii_ltrim_doc
ascii_rtrim_doc

Reporter: Nicola Crane / @thisisnic
Assignee: Nicola Crane / @thisisnic

PRs and other links:

• GitHub Pull Request #11074

_{Note: This issue was originally created as ARROW-13874. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson:
Issue resolved by pull request 11074
#11074