[feature] add a config option that allows us to use libsecret to fetch API keys

[mrcjkb]

Let's add a config option that allows us to use libsecret to fetch API keys,

Originally posted by @mrcjkb in #185 (comment)

[teto]

could be overkill, is it crossplatform ? looking at mail software, they often have a get_password_cmd setting .

[mrcjkb]

I don't think libsecret is crossplatform. I often use it with keepassxc. But a get_password_cmd might be a good alternative.