[R] Add bindings for filesystem API

[asfimport]

See ARROW-5494 for the Python bindings. Along with ARROW-6437, we'll be able to support file-system-like operations in S3. Some of this also may be necessary for the Datasets API bindings.

Reporter: Neal Richardson / @nealrichardson
Assignee: Romain Francois / @romainfrancois

Related issues:

• [R] Implement S3 file-system interface in R (is depended upon by)

PRs and other links:

• GitHub Pull Request #5390

_{Note: This issue was originally created as ARROW-6438. Please see the migration documentation for further details.}

[asfimport]

Romain Francois / @romainfrancois:
So we want R6 classes similar to these in python ? https://github.com/apache/arrow/pull/5258/files#diff-3bd5cc268dbe0b152f2f8ff9377fe6d4

[asfimport]

Neal Richardson / @nealrichardson:
Yeah, that's the idea.

[asfimport]

Neal Richardson / @nealrichardson:
Issue resolved by pull request 5390
#5390