Texture fetching

[parbenc]

add page explaining texture fetching in HIP

[neon60]

@parbenc please link the following pages in the document:

• https://rocm.docs.amd.com/projects/HIP/en/latest/doxygen/html/group___texture.html
• https://rocm.docs.amd.com/projects/HIP/en/latest/understand/programming_model_reference.html

[neon60]

Can we alse describe the different modes here:

https://rocm.docs.amd.com/projects/HIP/en/latest/doxygen/html/texture__types_8h.html

hipAddressModeWrap
hipAddressModeClamp  
hipAddressModeMirror  
hipAddressModeBorder

[neon60]

Please add figures for the different address and filter modes.

[MKKnorr]

I think some of the sampling methods need a better explanation.

And something I have been wondering: are sampling methods and address modes independent of each other? The sampling methods only show sampling within the indexable range, but don't explain out of range behaviour. If they are independent, then this should be highlighted better