Remove 'set' versions of graph phases from top-level cli

[ahal]

Taskgraph allows you to run the generation locally by specifying a phase of the graph generation. Currently these are:

• tasks
• full
• target
• target-graph
• optimized
• morphed

I can't think of any benefit of the tasks or target phases over their counter parts with edges (full and target-graph respectively). So I propose we drop them as cli subcommands (and rename target-graph to target):

• full
• target
• optimized
• morphed

I think this would make the cli much less confusing without compromising any functionality. The only downside is that generation might take teeny tiny bit longer.

[ahal]

Or alternatively if the edges are unnecessary when running locally, we could drop full and target-graph, and then rename tasks to full (I feel pretty strongly that the subcommand names should match up to what we colloquially name the phases)

[ahal]

One gotcha here is that we apparently add always_target_tasks between the target_set and target_graph phases. This feels wrong as I feel like those should also be part of the target_set.. but always_target_tasks had a lot of subtle behaviour, so it's possible it needs to be where it is for some reason.

I'm unclear whether keeping the ability to distinguish with/without these tasks on the cli is important or not.. but it's something to consider.

[jcristau]

FWIW I've used both target and target-graph in different cases. target to verify a target_tasks change was doing what I expected, and avoid noise from dependencies. target-graph when I wanted to include dependencies and see the whole thing to be scheduled.

[ahal]

That's a good point.. maybe we could keep target-graph due to that and my previous comment, and only drop tasks