s3: Add the OneFS SMB_VFS_CREATE_FILE implementation

s3: Add the OneFS SMB_VFS_CREATE_FILE implementation

This is the first pass at extending the onefs vfs module to support
the CIFS-specific enhancements available on OneFS.  Most of this patch
is massaging the sama open path to work with ifs_createfile.

ifs_createfile is a CIFS-specific syscall for opening/files and
directories.  It adds support for:
- Full in-kernel access checks using a windows access_mask
- Cluster-coherent share mode locks
- Cluster-coherent oplocks
- Streams
- Setting security descriptors at create time
- Setting dos_attributes at create time

This patch does not implement the samba side of the streams support or
oplocks support.  Tests that expect oplocks to be granted or streams
to be supported will fail.  This will be remedied in upcoming patches.