[CMake] Align package name with datasketches-cuda repository

The CMake project and installed package currently use `datasketches_cuda`, while the repository is named `datasketches-cuda`.

Rename the package-facing CMake artifacts and documentation so consumers use:

```cmake
find_package(datasketches-cuda CONFIG REQUIRED)
target_link_libraries(app PRIVATE datasketches::cuda)
```

The public target `datasketches::cuda` should remain unchanged.

Start by locating the CMake package configuration, installed package artifacts, and documentation references to datasketches_cuda. Check how the package name and public target are currently exported, then verify that consumers can use find_package(datasketches-cuda CONFIG REQUIRED) and target_link_libraries(app PRIVATE datasketches::cuda) without changing the public target.

Written by the indexing model from the issue text.