fabric: Rename fi_rx/tx_ctx_attr to just fi_rx/tx_attr

RX and TX contexts are objects allocated off of scalable
endpoints.  The attributes themselves apply to all transmit
and receive queues, including those belonging to normal
endpoints where an explicit RX/TX context will not be
referenced.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
fabric: Add 'injectdata' call

Provide an optimized interface that supports both injected
data and remote CQ data.  Applications, such as rsockets,
can make use of this feature.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
fabric: Rename fi_pendpoint to fi_passive_ep

Make the name of the function easier for user's to
figure out its usage.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>