refactor: Move logins into SQL table (#6724)

Move all `configured_*` parameters into a new SQL table `transports`.
All `configured_*` parameters are deprecated; the only exception is
`configured_addr`, which is used to store the address of the primary
transport. Currently, there can only ever be one primary transport (i.e.
the `transports` table only ever has one row); this PR is not supposed
to change DC's behavior in any meaningful way.

This is a preparation for mt.

---------

Co-authored-by: l <link2xt@testrun.org>

python/src/deltachat/testplugin.py

@@ -482,12 +482,8 @@ class ACFactory:
         addr = f"{acname}@offline.org"
         ac.update_config(
             {
-                "addr": addr,
-                "displayname": acname,
-                "mail_pw": "123",
                 "configured_addr": addr,
-                "configured_mail_pw": "123",
-                "configured": "1",
+                "displayname": acname,
             },
         )
         self._preconfigure_key(ac)