[migration] force 3.8.3 migration, and fix it (same_as not necessarily there, missing group change for max-post-length)

[forms] refactor action handling to ease overriding while keeping action overrideable by instance (closes #969167)

[web] dont attempt to update last login time on ldap users, avoiding spurious tb in logs (closes #914464)

[c-c] use logilab.database, not lgc.db

[sqlite] fix crash on db-create with sqlite abd unexistent database due to missing paren in logical expression (closes #909604)

[web] disallow authenticated users to access to the login form (closes #914873)

[reledit] #894131: use "<`attribute` unset>" instead of generic "<not specified>" when an attribute or relation has no value

[rql2sql] follow rql 0.26.1 changes: NOT nodes normalization, allowing simplification of sql generation, and fix #XXX

[repo] ensure thread is alive before calling .join. Closes #963580

[migration] add migration file commands to follow option group changes

fix 978144: exception with view send-email if empty subject

[test] fix test broken by introduction of adapters

[schema] fix same_as cardinality and bump Bookmark.path max length to approximative max url size

[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