[web] return 403 for Unauthorized, not 401 401 is reserved to HTTP authentication. Just because it's also called "unauthorized" doesn't mean it's the same as cubicweb's Unauthorized exception. Closes #3648809.

[test] update unittest_repoapi to 3.19 api (sic) [jcr: while at it, fix typos and add missing __main__ section]

[test] update unittest_utils to 3.19 api

[test] update unittest_rset to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[test] update unittest_rqlrewrite to 3.19 api

[test] update unittest_req to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[test] update unittest_predicates to 3.19 api [jcr: use self.admin_access instead of creating a new one each time]

[web/test] port unittest_reledit to RepoAccess API

[web/test] port unittest_magicsearch to RepoAccess API request created in setUp makes context manager usage painful, so create a context manager to do the setup for each test class.

[web/test] use real_error_handling context manager instead of open-coding it

[web/test] port unittest_idownloadable to RepoAccess API

[web/test] remove useless calls to self.request() from CORS tests

[web/test] port unittest_formfields to RepoAccess API

[web/test] port unittest_form to RepoAccess API

[web/test] port unittest_facet to RepoAccess API

[web/test] move unittest_controller to RepoAccess test API

[web/test] port unittest_breadcrumbs to 3.19 test api

[web/test] avoid deprecation warnings from find_entities()

[web/test] port unittest_application to new 3.19 API

[test] silence warnings for unittest_schema by upgrading to new 3.19 API

[test] silence warnings for unittest_cwctl by upgrading to new 3.19 API

[test] replace some assert{True,False} with more specific method

[test] silence warnings for unittest_entity by upgrading to new 3.19 API

Fix constraint sync during migration - restore constraints lost during merge in test schema. - use constraint_by_eid in BeforeDeleteCWConstraintHook as done in 3.17.14 for BeforeDeleteConstrainedByHook. Fixes handling of multiple constraints of the same type. - make sync_schema_props_perms() delete the CWConstraint entity instead of the constrained_by relation. In 3.19, the latter doesn't automatically result in the former just because the relation is composite. Simplify the constraint migration to delete all removed constraints and recreate new ones even if they share the same type; that optimization made the code more complicated for (AFAICT) no significant reason.

merge 3.18.4 into default server/test/unittest_migractions fails due to interaction between new constraint test (from 3.18) and composite deletion change (in 3.19).

Added tag cubicweb-version-3.18.4, cubicweb-debian-version-3.18.4-1, cubicweb-centos-version-3.18.4-1 for changeset 0176da9bc752

[test/data] Add missing 'add' permission on attribute Silences a warning introduced in 3.18.

[hooks/notification] Fix indentation Follow-up for changeset 1b8552265f3b "[hooks/notification] use a cnx not a session"

[devtools] deprecate CWTC.user()

minor cleanups