[doc] small rst fixes and cleanups in changelog files Related to #4832808

[doc] make the changelog chapter a one html page Related to #4832808

[doc] reformat changes files headers to remove the "what's new" phrasing and add the publication date instead. Related to #4832808

[doc] remove mentions of pyro and reposity instance type from the concepts chapter Related to #4832808

[doc] put the tutorials between the intro and the `Repository development` toc of the book Related to #4832808

[doc] move the documentations from docstring directly to the book. and improve a bit API documentations. Related to #4832808

[predicates] remove deprecated sentences in docstrings

[predicates] objectify the anonymous_user predicate for the sake of consistency.

[doc] more fixes of warnings/errors in doc build - move 3.21.rst changelog description at it's proper place - include changelogs in the main index - few typos - add :noindex: for autoxxx directives not in api/ Related to #4832808

[doc] fix warnings/errors in doc build - fix links to images - fix a couple of typos - re-add IDownloadableOneLineView doc - rename documenting.rst back to .txt, it's intended as a doc of how to write rst, not part of the rst doc Related to #4832808

[doc] Start documenting the API Related to #4832808

[doc] Remove useless indexes Related to #4832808

[doc] Insert the dev docs in the toc Related to #4832808

[doc] Restructure the documentation * Create a new index file * Move the sphinx configuration files do the documentation root * Move book/README to dev/documenting.rst * Move book/mode_plan.py to tools/ * Move book/en/images to images * Move book/en/* to book/ * Move changelogs to changes/* * Adapt the Makefile * Add a title to the javascript api index Related to #4832808

[migration/3.21.0] performance and reliability fixes - use EXCEPT instead of NOT IN, seems to improve performance dramatically on postgresql - delete rows from cw_<etype> tables whose eid is unknown - deal with missing/dangling required inline relations (by deleting the subject entities) instead of asserting - fix/improve print statements - don't ask for confirmation before running pure select queries

[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