Remove nodetypes hippo:skipindex, hippo:lock, hippo:lockable

hippo:skipindex usage is removed in REPO-2160 (v13.0), its nodetype can be removed with v14.0.

Note: this first requires an up-to-date local index with the hippo:skipindex usage removed, otherwise searching for their usages will not work.

This can either be ensured with a clean re-created index, or possibly through an cluster-notification to re-index (only those nodes). For the latter possibly a custom addon-checker mode can be devised.

As the hippo:lock/hippo:lockable nodetypes have been used in the past in combination with hippo:skipindex, safe removal of those was postponed (from REPO-2063) for likewise reason, but now can be combined with the removal of the hippo:skipindex.