[deprecation] fix 3.9 deprecation warning

no more Image type w/ cw 3.9

[fti] fix name conflict introduced by the new IFTIAdapter

[entity] clearing adapters cache in clear_relations_cache avoid weird caching issue, notably on repository session's user

[vreg] should raise exception on select ambiguity when running in test mode

[adapters compat] make implements_adapter_compat selector compatible with attributes

[test] no more Image type w/ cw 3.9

[adapters] refactoring fixes

[selectors] ensure selector return an int

[selectors] adaptable selector should not accept None in rset

[selectors] lltrace appobject_selectable selector

[selectors] allow to override `accept_none` value of EClassSelector / EntitySelector based selector by specifying a value in selection context

[selectors] move lltrace decorator and traced_selection cm to appobject module so we can apply lltrace to And/Or/Not selectors, fixing #662565

with cw 3.9, no more Image type

[vreg] on registration completed, don't crash if an object depends on an unexistant registry, simply kick the object out

[selectors] ensure adaptable('IDownloadable') takes precedence over implements('Any')