[Placeholder]Add support for reloading modules

[pragnagopa]

This is tracking issue to investigate the work needed on the python worker when JobHost restarts. As of now when JobHost restarts, python language worker is restarted as well. If a python worker is started in placeholder mode, on a jobhost restart -> functions host will send a new message JobHost restart event Python worker needs to :

• Reload modules for a python function https://docs.python.org/3.4/library/importlib.html#importlib.reload
• Clear any in-memory state

[pragnagopa]

cc @asavaritayal

[fabiocav]

@asavaritayal this work is blocked and beyond capacity for this sprint. So I'm moving this to Triaged.

[maiqbal11]

Spoke to @pragnagopa and this work is only required if we want to support live editing (i.e. Portal). Since that is not a mainline scenario, moving this down in priority.

[Hazhzeng]

Linux Dedicated, in portal editing, on save, JobHost restarts, may restart the Python worker.

• dependency resolution
• module reloading we need to confirm with the host team (may need to build a new infrastructure)

[stefanushinardi]

@vrdmr to take a look