Info mostro message

[arkanoider]

Added scheduled message with mostro infos - 5 minutes interval.

There was an error on file src\lightning\mod.rs line 161 here:

let invoice = decode_invoice(payment_request)?;
        let payment_hash = invoice.signable_hash();
        let hash = bytes_to_string(&payment_hash);
        let mostro_settings = Settings::get_mostro();

That function signable_hash did the trick, please check @grunch if it's right, seems we have the same result as before with just one call:

let invoice = decode_invoice(payment_request)?;
        let payment_hash = invoice.payment_hash();
        let payment_hash = payment_hash.to_byte_array();
        let hash = bytes_to_string(&payment_hash);
        let mostro_settings = Settings::get_mostro();