Add support for multiple input and output connectors

[ekneg54]

Is your feature request related to a problem? Please describe.

with #160 the connectors were split into seperate input and output sections. These sections are dictionaries as implemented.

Now I want to declare the connectors as a list to support multiple inputs and outputs.

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Additional context

All outputs should provide a config field to set it as the default output.
The goal should be to let logprep ship all messages to all default output but enable the predetector and the selective_extractor to ship to a different output targets with store_custom

The inputs should all be processed without any priority.