Closes https://github.com/chatmail/core/issues/7980.
Unpublished transports are not advertised to contacts, and self-sent messages are not sent there, so that we don't cause extra messages to the corresponding inbox, but can still receive messages from contacts who don't know the new relay addresses yet.
- This adds `list_transports_ex()` and `set_transport_unpublished()` JsonRPC functions
- By default, transports are published, but when updating, all existing transports except for the primary one become unpublished in order not to break existing users that followed https://delta.chat/legacy-move
- It is not possible to unpublish the primary transport, and setting a transport as primary automatically sets it to published
An alternative would be to change the existing list_transports API rather than adding a new one list_transports_ex. But to be honest, I don't mind the _ex prefix that much, and I am wary about compatibility issues. But maybe it would be fine; see b08ba4bb8 for how this would look.
Otherwise it's not possible to write tests reliably because sync messages may be executed multiple
times if they arrive from different transports. This should fix flaky
`test_transport_synchronization`.
Also always emit `TransportsModified` if the primary transport is changed by a sync message, even if
it doesn't contain `SyncData::Transports`.
Also don't decrease `add_timestamp` in `save_transport()` if nothing else changes, this doesn't make
sense.
Fix get_secondary_addrs() which was using
`secondary_addrs` config that is not updated anymore.
Instead of using `secondary_addrs` config,
use the `transports` table which contains all the addresses.
`login_param` module is now for user-visible entered login parameters,
while the `transport` module contains structures for internal
representation of connection candidate list
created during transport configuration.
