[ENH] Use RAFT error handling mechanism

[seunghwak]

Describe the solution you'd like
RAFT error handling macros are updated (rapidsai/raft#15). We need to use this instead of redefining our own (our CUGRAPH_EXPECTS and CUGRAPH_FAIL need to be updated to use the RAFT mechanism).

[afender]

So should we just use RAFT_EXPECTS/RAFT_FAIL until we have a use case for cugraph specific error macros?
We will just keep reconciling them otherwise.
IIRC the only difference is the "raft" vs "cugraph" string in the error message

[afender]

Let's also upgrade the RAFT git tag in the cmake to get the latest RAFT version that contains rapidsai/raft#15

[afender]

And there are many redefined warnings (CUDA_TRY, CUDA_CHECK, THROW). They need to be deleted from cuGraph

[seunghwak]

So should we just use RAFT_EXPECTS/RAFT_FAIL until we have a use case for cugraph specific error macros?
We will just keep reconciling them otherwise.
IIRC the only difference is the "raft" vs "cugraph" string in the error message

CUGRAPH_EXPECTS(FAIL) will throw cugraph::logic_error while RAFT_EXPECTS(FAIL) will throw raft::logic_error in addition to the difference in error message.

And cuDF uses CUDF_EXPECTS (cuML currently uses ASSERT but I guess they will switch to CUML_EXPECTS) and I think we'd better use CUGRAPH_EXPECTS(FAIL) and use this for now.

[seunghwak]

I assigned this to myself. This will be a quick fix.