Ensure that the webserver is robust

[fntlnz]

What would you like to be added:

We need to make sure that the webserver is robust enough, here some action items:

• Input parsers should work in most of cases, if they don't make sure exceptions are handled correctly Crash with Invalid JSON error while parsing container info #683
• No connection should be able to crash the webserver itself, it happened in the past, we need to make sure it doesn't anymore Fix webserver errors #759
• Exceptions in the webserver should all be their own, we can't have all generic exceptions or just `sinsp_exception)

[stale]

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