cubicweb #3526594 [source/native] give create_eid the ability to reserve many eids at once [validation pending]

Currently, create_eid uses a side connection & transaction for each new issued eid.
In some situation this cost should be alleviated.

prioritynormal
typeenhancement
done in3.19.0
load1.000
load left0.000
closed by#3f5b59527d31 [source/native] allow many eid creation per .create_eid call (closes #3526594)
patch[source/native] allow many eid creation per .create_eid call (closes #3526594) [applied][pkg] bump the dependency on logilab.database [applied][source/native] refactor eid generation code [applied]