cubicweb #5414754 [dataimport] rewrite cwxmlparser and ldapparser using new dataimport API [validation pending]

rewrite the parser api using the Generator concept explained in #5414753 so dataimport and source api converge, and allows deprecation of the whole extid2eid machinery.

done in3.22.0
load left0.000
closed by<not specified>
patch[datafeed] test and fix deletion of externaly deleted entities [rejected][datafeed/dataimport] rewrite cwxml parser using the importer API. Related to #5414754 [rejected][datafeed] gives information about moved entities to the parser [applied]