elementwise op (#238)

* Add elementwise operation kernel and example

* Add comment

* Add template argument of dim . Prepare to support multiple dimension

* Rename example

* Support 1 dimension

* Add static assert

* Add comment

* Extract pad

* Remove redundant argument

* Support any dimension for elementwise operation

* Remove line

* Let it be the multiple number of CU

* Move thread per block to the parameter of constructor

* rename threadPerBlock with blockSize

* Support double

* rename kernel function name

* remove redundant include header

* Refine type

* Need to the final dimension

* Refine variable name

* Refine type

* Use index_t instead of int in API

Co-authored-by: rocking <chunylai@amd.com>

[ROCm/composable_kernel commit: aafc3ac27a]

library/include/ck/library/host_tensor/host_utility.hpp

@@ -0,0 +1,17 @@
+#pragma once
+#include <vector>
+
+namespace ck {
+
+template <typename Src, typename Dst>
+inline std::vector<Dst> convert_vector_element_type(const std::vector<Src>& inData)
+{
+    std::vector<Dst> outData;
+
+    for(auto elem : inData)
+        outData.push_back(static_cast<Dst>(elem));
+
+    return (outData);
+};
+
+}; // namespace ck