Previously Delta Chat tried to use local part of email address as well.
This configuration is very uncommon,
but trying it doubled the time of configuration try
in the worst case, e.g. when the password is typed in incorrectly.
Trying non-strict TLS checks is not necessary
for most servers with proper TLS setup,
but doubles the time needed to fail configuration
when the server is not responding, e.g.
when all connection attempts time out.
There is also a risk of accidentally
configuring non-strict TLS checks in a rare case
that strict TLS check configuration spuriously failed,
e.g. on a bad network.
If the server has a known broken TLS setup,
it can still be added to the provider database
or configured with non-strict TLS check manually.
User can also configure another email provider,
such as chatmail servers, instead of using the server
with invalid TLS hostname.
This change does not affect exising setups.
* Configure: Try "imap.*"/"smtp.*"/"mail.*" first
Fix half of #3158.
Try "imap.ex.org"/"smtp.ex.org" and "mail.ex.org" first because if a server exists
under this address, it's likely the correct one.
Try "ex.org" last because if it's wrong and the server is configured to
not answer at all, configuration may be stuck for several minutes.
* Changelog
* Add test
LoginParamNew structure, which contained possible IMAP and SMTP
configurations to try is replaced with uniform vectors of ServerParams
structures. These vectors are initialized from provider database, online
Mozilla or Outlook XML configuration or user entered parameters.
During configuration, vectors of ServerParams are expanded to replace
unknown values with all possible variants, which are tried one by one
until configuration succeeds or all variants for a particular protocol
(IMAP or SMTP) are exhausted.
ServerParams structure is moved into configure submodule, and all
dependencies on it outside of this submodule are removed.
