Flake8 bits with some copyright updates

[test] Use plain unittest in unittest_views_forms.py

Some py3k related fixes: use text_type instead of unicode

[cwctl] Kill deprecated ordered_instances method no need to keep bw compat for this.

[test/cleanup] Use plain unittest

[test/cleanup] flake8 unittest_rqlannotation.py

[debian] logilab >= 1.2.2 in requires (only in build depends) Related to #16404515.

[debian] move unittest2 to requires not recommends closes #16404515

[devtools] named context for boxes subTest for consistency

Added tag 3.24.3, debian/3.24.3-1, centos/3.24.3-1 for changeset bb5904cd284e

[pkg] 3.24.3

[cwconfig] ensure CubicWebNoAppConfiguration returns a typed value (closes #16364459)

[views/optimization] Makes has_editable_relations predicate less costly by using generator The `has_editable_relations` predicate is used to say if the 'modify' action should appear. To do so, it checks if anything is editable (ie. something in the attributes, relations or inlined section of the automatic form). This may be costly since it may have to check several permissions. To optimize this a bit, this cset turns list into generator so that we'll avoid unnecessary work as soon as we find a match.

[cwconfig] Trim down allowed exceptions in gettext language setting I can't see any valid reason to pass on ImportError and AttributeError. In particular, the latter shadowed a Python 3 error until 4f43e64603ef.