[serverctl] fix source-sync command Closes #5491700

[server] missing import Fixes NameError in an unlikely error case.

[server/test] stop using email cube - make unittest_migractions use a separate datadir, and add a fake email cube there (we use it to test {add,drop}_cube, so need something that looks like a cube) - for the other test modules, just copy what we need from cubicweb-email's schema to our test schema

[web/views] Remove unused variable

[server/session] bring anonymous_connection back Fixes cubicweb-comment.

[migration/3.21] idempotency fixes Drop constraints before (re)creating them This is postgresql-specific syntax, sqlserver needs work.

[migration/3.21] Make index and table creation idempotent

[migration/3.21] Add missing foreign keys when upgrading Try to delete dangling relations, since there's no point in keeping them. Related to #4846892.

[schema2sql] properly consider skip_relations parameters. This is the same bug as yams #286912. Also, introducing a unique function telling if the relation should have a table or not unhide some other problems related to computed relation, or missing skipped relations information.

[hooks/test] don't rely on RelationDefinition implicitly Its presence in globals is deprecated and going away.

[web] write css_class to attrs on rendering and not on button creation Because css_class attribute may be overriden by bootstrap after button creation and this modification has to be taken into account. closes #5457548

[statsd_logger] handle ipv6 addresses

implement a simple statsd logger (closes #5488711) and add a few timing probes on: - etwist.server.CubicWebRootResource.render_request() - server.querier.QuerierHelper.execute() - server.sources.native.NativeSQLSource: - sqlexec() - compile_rql() - authenticate() - doexec() - doexecmany() as well as a pair of counters on server.querier.QuerierHelper cache (hit/miss).

[predicates] ExpectedValuePredicate now accepts a dict parameter ``match_form_params`` and ``match_kwargs`` benefit from that. For instance, the following statements are valid:: __select__ = match_form_params('vid', 'subvid') __select__ = match_form_params(vid='list', subvid='incontext') __select__ = match_form_params(vid=('list', 'tsearch')) In the latter cases, not only the parameters (``vid``/``subvid``) must be in the request form but their corresponding value must also match the expected values (or one of possible choices if `values` is a sequence). closes #5484070

[rql2sql] Fix iter_exists_sols() excessive cleaning of _state.tables Closes #5503548

[cwctl] allow overriding config settings from the command line (closes #5557656) eg. cubicweb-ctl start -p port:8082 myapp to overload the port parameter defined in the all-in-one.conf file.

avoid sanitizing warnings

[devtools] avoid warning about source['global-db-name'] sqlite and postgres db handlers store the db template name there.

[skeleton] remove no-break space from skeleton setup.py

[server/test] drop unused import

[doc] update 3.21 release notes

[devtools] Sort _cw_fields in fake_form Try to generate a predictable string, to help testing with PYTHONHASHSEED=random.

[entity] sort fetchattrs when generating rql Try to generate a predictable rql query, to help testing with PYTHONHASHSEED=random.

Update hgignore for temporary test databases