PtrListOps and adjustments for sync

• spillover from 2020 that was too close to release time.
• conciser form when handling cyclic and processor patches (avoids double dynamic_cast).

changed milestone to %v2106

added enhancement label

changed target branch from master to develop

• Mattijs is happy with the cleanup
• now passing tutorial tests. Previously had one regression in overInterDyMFoam/boatAndPropeller. Using global data for the processor-patches appears to be ill-advised in some portions of syncToolsTemplates since these may be called from within globalMeshData itself. Could probably have a workaround with additional tag etc but doesn't seem worth it at the moment.

approved this merge request

mentioned in commit aa9cd50d

merged