Extend Flowgentic with executable tool as a task

[AymenFJA]

Hi all, this is a feature request.

FlowGentic is missing a type of task that is required by most of our applications on HPC:

similar to this

AsyncFlowType.FUNCTION_TASK

We would like to have:

AsyncFlowType.EXECUTABLE_TASK

Where executable can be: example.py or it can be a binary such as ./calac_math that can be passed to Asyncflow as:

@flow.executable_task