Ballista Executor report plan/operators metrics to Ballista Scheduler

[mingmwang]

Which issue does this PR close?

Partial closes #116. There are still some pending changes need to be made to the DataFusion code base. Basically this PR covered those parts:

1. Enhance rpc protocols to report task metrics rpc UpdateTaskStatus (UpdateTaskStatusParams) returns (UpdateTaskStatusResult) {}
2. When the task finish, collect the plan metrics and report back to Scheduler
3. In Scheduler side, merge and aggregate task metrics to stage metrics, update the ExecutionGraph.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[mingmwang]

@thinkharderdev @andygrove

Please help to review my PR.

[alamb]

is there any other comments or concerns to be resolved before merging this PR? I haven't been following ballista closely so I don't know who has been merging the PRs recently

[mingmwang]

@andygrove @thinkharderdev Can we merge this PR first? We can have ongoing PR to track the proper place for metrics and task status storage.