Implement parallel resource execution

[a-hilaly]

TLDR; We need to enhance Symphony's resource execution to allow for parallel processing of independent resources.

Currently, Symphony's execution model is linear: resources are executed in waves based on a topology sort of the dependency graph, with each wave contains one resource. This approach, while ensuring correct dependency order, doesnt take advantage of potential parallelism where resources are not dependent of each other. We need a new implementation to optimize these waves to allow multiple independent resources to be grouped into the same wave.