chore: move CircleCI config back in #4

Job	Run time
Checking fmt	15s
Clippy	2m 4s
Test with CPU (--workspace)	3m 13s
Test (Test OpenCL only, --workspace --release --features opencl)	4m 0s
Test with CPU (--workspace --no-default-features)	3m 13s
Test (Test CUDA only)	3m 59s
Test with CPU (--release -- --ignored)	32m 50s
Test (--release --features cuda)	4m 1s
Test (Test CUDA/OpenCL (CUDA at run-time), --release --features cuda,opencl, cuda)	3m 57s
Test (Test CUDA/OpenCL (OpenCL at run-time), --release --features cuda,opencl, cuda)	3m 58s
Test (Test SupraSeal, --release --features cuda-supraseal)	3m 40s
	1h 5m 10s

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