rules_r/razel: use pkgType option for binary pkg availability
rules_r/razel: use pkgType option for binary pkg availability

Summary:
Only the official version of R from CRAN supports binary packages. If
the user has R installed from any other source, binary packages are not
supported. We can not assume that all Darwin installs support binary
packages.

Reviewers: joshnewman

Reviewed By: joshnewman

Differential Revision: https://phabricator.grailbio.com/D15648

fbshipit-source-id: 3779a8f

grailbio/rules_r,grailbio/rules_r,grailbio/rules_r,grailbio/rules_r,grailbio/rules_r