cubicweb-vcsfile #2532125 Make VCSFile not provide "write access" though the web by default [validation pending]

Current implementation of VCSFile includes controllers to upload revisions from the web. These should be disabled by default.

priorityimportant
typeenhancement
done in1.12.3
load left0.000
closed by#4ba06c8d6eb1 [views/actions] anonymous should not see write actions (closes #2532125)
patch[views/actions] anonymous should not see write actions (closes #2532125) [applied]