(10/n - non-xlformers conda-on-mast mvp)(monarch-fb/BUCK) Include torchx-fb as part of monarch.whl (#439)

Summary:
Pull Request resolved: #439

To bundle torchx-fb (with internal plugins such as being able to launch on MAST) build the wheel with:

```
buck build @//mode/opt --show-full-simple-output --config monarch_whl.include=torchx //monarch/python/monarch:monarch.whl
```

To install:

```
pip install --force-reinstall --no-deps $(BUILD_CMD_ABOVE)
```

WARNING: monarch + torchx doesn't work yet! this is why it is behind the `--config monarch_whl.include=torchx`! I'm landing this so that others can repro the error and I can get help fixing it.

## Repro Instructions:

```
$ $HOME/fbsource/genai/xlformers/dev/xl_conda.sh xlformers_finetune_conda:stable

$ cd ~/fbsource/fbcode

$ pip install --force-reinstall --no-deps $(buck build @//mode/opt --show-full-simple-output --config monarch_whl.include=torchx //monarch/python/monarch:monarch.whl)

$ cd ~/fbsource/fbcode/scripts/kiuk/examples/monarch_conda
$ python main.py
```

should fail with

```
import monarch._rust_bindings
ImportError: /home/kiuk/.fbpkg_conda_envs/xlformers_finetune_conda-9648802/lib/python3.10/site-packages/monarch/../monarch/lib/libomnibus.so: undefined symbol: __kmpc_fork_call
```

Reviewed By: highker

Differential Revision: D77411375

Author: kiukchung

python/monarch/tools/commands.py

@@ -21,7 +21,7 @@
 )
 
 from monarch.tools.mesh_spec import mesh_spec_from_metadata, ServerSpec
-from torchx.runner import Runner
+from torchx.runner import Runner  # @manual=//torchx/runner:lib_core
 from torchx.specs import AppDef, AppDryRunInfo, AppState, CfgVal, parse_app_handle
 from torchx.specs.builders import parse_args
 from torchx.util.types import decode, decode_optional