Instead of stuffing host/port/user/etc into CamelURLs.
To enforce this in 3rd party extensions, remove EAccounts from
EMConfigTargetAccount and rename it EMConfigTargetSettings with
the following struct members:
const gchar *email_address;
const gchar *storage_protocol;
CamelSettings *storage_settings;
const gchar *transport_protocol;
CamelSettings *transport_settings;
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