Use spf13/viper for managing the configuration file

[claudiodangelis]

This PR adds viper configuration management.
Major changes:

• configuration file will now use YAML rather than JSON
• configuration parameters will be also read from the environment variable using the QRCP_ prefix

I'm still unsure whether or not we should add a function to automatically migrate the old JSON configuration file to YAML.

What is still missing:

• README update
• Proper testing of environment variables
• Add migrate function to transparently migrate to the new YAML configuration file

[leestarb]

This is a good migration :). However I'd like to see backward compatibility with the JSON.

[claudiodangelis]

Hey @leestarb , thanks for checking in, there will be a function to automatically migrate to YAML at tool startup: https://github.com/claudiodangelis/qrcp/blob/0236150643d4a7358acd0f3ed1bda6853221d882/config/migrate.go

[leestarb]

Hey @leestarb , thanks for checking in, there will be a function to automatically migrate to YAML at tool startup: https://github.com/claudiodangelis/qrcp/blob/0236150643d4a7358acd0f3ed1bda6853221d882/config/migrate.go

No, no, no. Such function should change the config file ONLY if the user wants it. Otherwise this should convert it BUT not change the original file, like using converted one that was moved to the temp folder!

That is what I suggest :)

[claudiodangelis]

Hello @leestarb , I followed your advise and removed the automatic migration, thanks!