cubicweb #5456849 Allow to use cwclientlib for datafeed sources [validation pending]

so we can easily use signedrequest for authentication

priorityimportant
typeenhancement
done in3.21.0
load0.500
load left0.000
closed by#4c59409220b6 [datafeed] allow to use cwclientlib for datafeed's queries (closes #5456849)
patch[datafeed] allow to use cwclientlib for datafeed's queries (closes #5456849) [applied][cwxml parser] refactor url handling code to use urlparse and urlencode (related to #5456849) [applied]