Previously MX records were queried only for OAuth 2 configuration and
did not affect the list of servers tried. User was required to manually
configure the servers for Google Workspace (former GSuite) domains.
Now MX records are queried during configuration. If provider is found in
offline database, its ID, corresponding to the filename, is saved as
`configured_provider`.
`configured_provider` is also set during database migration if email
address uses the domain from the provider database, but no MX querying
is done.
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.
