Add support for versioned loading of libs at runtime; Fix cudnn cmake install command

[9prady9]

Description

• Added support for loading versioned libraries by DependencyModule class. If versioned library is not found, the search will fallback to non versioned name lookup.
• Changed cudnn module to lookup latest minor releases for each major version available.
• Earlier to this change, cuDNN install command failed on windows. On Linux, it was packaged with incorrect version suffix.
  After this change, cuDNN library will be installed as <lib prefix>cudnn<lib suffix><soname> on unix platform.

Changes to Users

None

Checklist

• Rebased on latest master
• Code compiles
• [ ] Tests pass
• [ ] Functions added to unified API
• [ ] Functions documented

[9prady9]

Leaving sample output of versioned loading for reference.

[platform][1593503872][042598] [ ../src/backend/common/DependencyModule.cpp:62 ] Attempting to load: libforge.so
[platform][1593503872][042598] [ ../src/backend/common/DependencyModule.cpp:65 ] Found: libforge.so
[platform][1593503872][042598] [ ../src/backend/cuda/device_manager.cpp:427 ] CUDA Driver supports up to CUDA 10.2 ArrayFire CUDA Runtime 10.2
[platform][1593503872][042598] [ ../src/backend/cuda/device_manager.cpp:495 ] Found 1 CUDA devices
[platform][1593503872][042598] [ ../src/backend/cuda/device_manager.cpp:517 ] Found device: GeForce GTX 1060 3GB (2.94 GB | ~3754.03 GFLOPs | 9 SMs)
[platform][1593503872][042598] [ ../src/backend/cuda/device_manager.cpp:556 ] AF_CUDA_DEFAULT_DEVICE: 
[platform][1593503872][042598] [ ../src/backend/cuda/device_manager.cpp:574 ] Default device: 0(GeForce GTX 1060 3GB)
ArrayFire v3.8.0 (CUDA, 64-bit Linux, build 703a1fdc8)
Platform: CUDA Runtime 10.2, Driver: 440.100
[0] GeForce GTX 1060 3GB, 3012 MB, CUDA Compute 6.1
[mem][1593503873][042598] [ ../src/backend/cuda/memory.cpp:158 ] nativeAlloc:    1 KB 0x7f69c4600000
[platform][1593503873][042598] [ ../src/backend/common/DependencyModule.cpp:95 ] Attempting to load: libcudnn.so.7.6.5
[platform][1593503873][042598] [ ../src/backend/common/DependencyModule.cpp:98 ] Found: libcudnn.so.7.6.5
[platform][1593503873][042598] [ ../src/backend/cuda/cudnnModule.cpp:85 ] cuDNN Version: 7.6.5 cuDNN CUDA Runtime: 10.0
[platform][1593503873][042598] WARNING: ArrayFire CUDA Runtime(10.2) and cuDNN CUDA Runtime(10.0) do not match. For maximum compatibility, make sure the two versions match.(Ignoring check)
[platform][1593503873][042598] [ ../src/backend/cuda/platform.cpp:118 ] Initializing cuDNN

[umar456]

Couple of minor comments. They are not major.