Resubmit "Add `RpcAgentOptions` struct type, which bundles different required arguments for different `RpcAgent`s" (#30093)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30093
https://github.com/pytorch/pytorch/pull/28226 introduced `worker_to_id` arg to the `def init_rpc` function for other `RpcAgent`. While it's not really used by `ProcessGroupAgent`. Cleanup is wanted for this, as described in https://github.com/pytorch/pytorch/issues/29031.
To adapt to the difference of different `RpcAgent`, adding a `RpcAgentOptions` base classes, which allow leveraging inheritance to add extra fields.
ghstack-source-id: 94197295
Test Plan:
### OSS RPC + RRef tests
```
buck test mode/dev-nosan //caffe2/test:rpc_fork
```
```
buck test mode/dev-nosan caffe2/torch/fb/distributed/thriftRpcBackend/test:thrift_rpc_fork_test -- test_sync_rpc
```
### Prototype RRef tests
```
buck test mode/dev-nosan caffe2/torch/fb/distributed/pytorch/tests:test_rpc
```
```
buck test mode/dev-nosan //caffe2/torch/fb/distributed/pytorch/tests:test_rpc_thrift_rpc_agent
```
### Dist autograd
```
buck test mode/dev-nosan caffe2/test:dist_autograd_fork
```
```
buck test mode/dev-nosan caffe2/torch/fb/distributed/thriftRpcBackend/test:thrift_dist_autograd_fork_test
```
Differential Revision: D18595578
fbshipit-source-id: 616fca3b844c171ed5277bbc6a2b1693bc3a8065
