libfabric-2.0: Add option for not supporting any source receive

[j-xiong]

Supporting any source receives is often associated with performance penalty. A provider may choose to only support receive from explicit source, i.e., FI_DIRECTED_RECV + not allowing FI_ADDR_UNSPEC. In such case, we want to have a mode bit to indicate such limitation.

[j-xiong]

See #10317