[Dependency Graph] Track the development of the dependency graph

[willianrampazzo]

This is an epic issue to track the development of the dependency graph. New tasks will be added here when needed.

• [x] #5202
• [x] #5203
• [x] #5204
• [ ] #5205

[pevogam]

Just a quick feedback on this one since I mimicked @willianrampazzo approach here to spawn pre- and post-tasks for each test task - our scheduler became roughly 50% slower once we did this which makes me suspect that spawning a separate pre- and post-task for each test (e.g. to collect sysinfo data) might drag down the graph execution too much. More info and context in: https://github.com/avocado-framework/avocado/discussions/5681#discussioncomment-6096295.