Allow specifying API keys and other configuration secrets via filepath:

[korfuri]

Right now the filepath: prefix allows keeping the list of archive passwords in a separate file. However the mechanism is not generalized to other sensitive values, i.e. the api_key parameters for the various *arrs. This makes it slightly awkward to integrate with secret management systems for these keys.

Would it be possible to generalize the filepath: prefix system to all options, or to all potentially-sensitive options instead?

Thanks!