support multiple recepients in mail sender

[hairmare]

Right now it only supports a single, to, cc, or bcc recipient. This leads to fun situations where configuring multiple cc addresses in the config file leads to only the last address specified being used as a cc recipient instead of it composing a mail with multiple cc recipients.

We should allow specifying the relevant params several times and allow composing mails with several to, cc, and bcc recipients,

[hairmare]

The new YAMLConfigParser from https://github.com/bw2/ConfigArgParse#config-file-syntax might also be worth checking out to make multiple recipients a list on the config file.

[hairmare]

comma separated values work tho

[hairmare]

implementing this properly would include validation, given that commas work i'm closing this is a not planned