Allow specifying config.json on command line

[s-ol]

When osc-bridge is installed on the system with npm i -g osc-bridge or run via npx, it would be nice to still be able to specify the options. However the way the options are currently being read doesn't work in those cases (even by creating a package.json in the current directory).

It would be nice to be able to pass a path to a config.json that has the same shape as package.config.osc-bridge, so that the tool can be used more effectively standalone.

[olange]

Many thanks for this proposal and the Pull Request. I'll check it in next week, as I am currently on the road with limited Internet connexion and only a tablet.