Job launcher

[yhwen]

Fixes # .

Description

Added the job launcher API. Each site will have the ability to choose how to launch the job to run. Currently only support the client side job launch. There are 2 launchers to choose from, ProcessJobLauncher, or K8sJobLauncher. The job launcher is configured in the local/resources.json components like this:

  {
    "id": "process_launcher",
    "path": "nvflare.app_opt.job_launcher.process_launcher.ProcessJobLauncher",
    "args": {}
  }

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Quick tests passed locally by running ./runtest.sh.
• In-line docstrings updated.
• Documentation updated.

[yanchengnv]

Please change to use event to select launchers, as we discussed before. This will make our core code completely free of launcher specific knowledge (e.g. image).
Define a set of standard return codes for the "poll" method.
No need for "can_launch" method in Launcher Spec.
See comments for detail.

[yanchengnv]

Not quite there yet:

• The return code of poll() should be standardized.
• The condition for checking job_launcher isn't right.
• See other comments for improvement in other areas.

[yanchengnv]

Looks okay. See my comments for return code improvement that can be done in another PR.

Also need another PR to modify job_meta_validator.py to support the new deploy_map format.

[yhwen]

/build

[YuanTingHsieh]

/build

[YuanTingHsieh]

/build

[yhwen]

/build

[YuanTingHsieh]

/build