algorithm: check DescriptorType when creating pool

The function that was prevously used, `mem->type()`, is not explicitly
the same as the descriptor type, so using `mem->getDescriptorType()` is
more accurate.

It also makes it easier to create new image-like subclasses of
`kp::Memory` because as long as they specify the correct descriptor
type, the correct pools will be created.

Author: ahem

src/Algorithm.cpp

@@ -134,7 +134,7 @@ Algorithm::createParameters()
     KP_LOG_DEBUG("Kompute Algorithm createParameters started");
 
     for (const std::shared_ptr<Memory>& mem : this->mMemObjects) {
-        if (mem->type() == Memory::Type::eImage) {
+        if (mem->getDescriptorType() == vk::DescriptorType::eStorageImage) {
             numImages++;
         } else {
             numTensors++;