Change SUBDIR destination to REMOTE_SUBDIR

In preparation for the ability to sync to a remote subdirectory (as
opposed to only the static component root). By default we deploy to the
DocumentRoot of the site but we add the ability to override this path
using CI variables.
1 job for !22 with remote-subdir in 29 seconds (queued for 9 seconds)
latest detached
Status Name Job ID Coverage
passed test #57832