[cwxml parser] minor pylint fixes

[devtools] make CubicWebTC.login as admin undo previous logins Fixes things when login is not used as a context manager.

[devtools] fix self.session._cnx vs self.cnx._cnx confusion after self.login Make sure the client connection and the session refer to the same server connection.

[devtools] _orig_cnx does not exist any more (missing change)

[c-c schema] option to show single etype (closes #3404831)

[multi-sources-removal] Drop entities.source column Since we remove federated multi-sources support, the same value ('system') is always stored in this column and so could be removed. Also, cleanup repository caches and a few api where the very same useless information could be removed. Closes #2919300, at last [jcr: restore sanity check of etype against schema in checkintegrity.has_eid]

[repo] pylint cleanup, mainly of imports, with a bit of style

[multi-sources-removal] Drop no more used federated ('true') multi-sources related code Related to #2919300 (almost done!)

[multi-sources-removal] Turn ConnectionsSet into simpler ConnectionWrapper also, SqliteConnectionWrapper becomes a subclass. This is allowed since now ConnectionsSet responsability has been reduced to handling the system source only. This changeset also: * drops useless cnxset_set / check_connection api * deprecates former .source / .connection / container api but it renames neither the session's cnxset attribute, nor the related repository method. Related to #2919300

[multi-sources-removal] Drop cnxset_freed from source interface Though a hack is still needed when using sqlite Related to #2919300

[cnxset] add backwards compat for cnxset.source_cnxs It's used at least in a vcsfile migration script.

[multi-sources-removal] Simplify ConnectionsSet internal structures and public methods since it now handles a connection to the system source only Related to #2919300 [jcr: adjust 3.17.11 migration, fix a number of bugs in new ConnectionsSet implementation, fix source.{open,close}_source_connections]

[ldap] simplify connection handling since we deleted ldapuser source, we don't need anymore the get_connection and ConnectionWrapper stuff (that was used to put the ldap connection into the cnxset). Also, we should simply let connection errors propagate so this is properly reported to import logs.

[ldap] merge cw.server.ldaputils back into ldapfeed source we don't need separated modules since ldapuser source has been removed

[config] cleanup/refactor server sources file values handling * kill former `sources` method, misnamed since we've only the system source configuration in the sources file (and some default admin account information) * introduce new system_source_config and default_admin_config properties to access to the two information in this file Then use one or the other when appropriate

[repoapi] drop get_option_value's foreid argument repoapi was introduced in 3.19, so no need to introduce legacy deprecated stuff at the same time.

[multi-sources-removal] Drop foreid argument of repo.get_option_value It doesn't need it anymore. Related to #2919300

[c-c restore] drop useless restore-all option, and related systemonly argument

[multi-sources-removal] Kill repo.sources there is only the system source in there now! Related to #2919300

[multi-sources-removal] Drop no more necessary scleanup (source cleanup) argument Related to #2919300

[multi-sources-removal] drop source location search on glob_*[entity|relation] methods source is now always the system source Related to #2919300 [jcr: fix wrong rebase in symmetric relation removal]

[server test] simplify data-schemaserial test instance's schema

[multi-sources-removal] Drop (dont_)cross relation related code That was only needed for now deleted 'true' multisources. Related to #2919300 [jcr: also remove it from server/test/data-schemaserial/schema.py]

[multi-sources-removal] Simplify repo.delete_info_multi arguments, uri is no more used Related to #2919300

[multi-sources-removal] Drop deleted_entities system table and entities.mtime column since they were only used by the entities_modified_since api of the repository which has been dropped. Along with them, the multi-sources-etypes configuration variable and some sql queries at modification/deletion time of entities. Bon vent ! Related to #2919300

[multi-sources-removal] drop repository entities_modified_since public api actually only used by pyrorql/zmqrql sources which have been dropped. This will allow to drop a bunch of system meta-data (eg deleted_entities) Related to #2919300

[multi-sources-removal] Drop the "true" multi-sources planner Only keep copy-based sources. This will soon allow for greater code simplification. Related to #2919300

[multi-sources-removal] Drop cw.server.sources.extlite no more used for a while, beside an utility class Related to #2919300