[webctl] Generate static data directory on upgrade (closes #2167873) - if the folder already exists, ``upgrade`` asks for deletion, - add an option (``generate-staticdir``) to allow skipping this task. - add an option (``staticdir-path``) to specify the static data folder path. The ``gen-static-datadir`` command allows to specify the target folder but there is otherwise no way to retrieve this information during upgrade.

[cwctl] Don't check for old lgc versions Support for check_duplicated_command in CommandLine was added in 2011 for 0.55, and we already depend on 0.59.0.

[migration/3.18] add sanity checks before changing symmetric relations Delete supposedly impossible relations from the db. Related to #3259713.

[migration/3.18] disable all hooks when setting up symmetric relations This operation is semantically a no-op, so it should be invisible for the application. Related to #3259713.

[devtools] bases for instrumenting / debugging standard propagation hooks * a class that helps writing command to check propagation, detecting standard errors and picture the propagation as a graph * a class to instrument sets used to configure standard propagation hooks closes #3171980

instrument cwvreg, so we may know what's being loaded by asking the registry store

set proper PACKAGE information for yams 0.39 Yams 0.39 adds an unobstrusive API to get the package, or cube, defining a part of the schema (entity type, relation type/def). As CubicWeb overrides part of the schema reading process, we have to handle this information on our side so it will be properly set.