[IMPL] Texture1D2D3D Sample

[IngmarBitter]

Extension of the Texture3D Sample to merge on the same quad texture images from two different textures, one 2D and the other 3D. Thus demonstrates how to allocate and access multiple textures.

[IngmarBitter]

Converted to draft. It is a mix of changes relevant to the PR title and others that are general TerraFX Samples improvements. The latter will be extracted as separate smaller PRs.

[IngmarBitter]

All review issues are fixed. Unfortunately, the display of Texture1D2D3D is not correct. It looks like the three texture samlers get their data from the same memory region. So in the allocation of the texture region inside the textureStagingBuffer the offset is set to 0.