Option to produce summary/truncated format rndc dumpdb (with indication of size of full dump)

Description

It's often useful for troubleshooting an issue to obtain a cache dump ('rndc dumpdb -all') but at the same time, operators may have concerns about how large the output file will be as this cannot easily be anticipated (some RRs are much larger in display than in wire format - see also issue GL #795

Request

It could be very helpful therefore to have a new option -truncated for dumpdb that limits the size of each individual RR being dumped, but additionally while doing so, indicated which RRs have been truncated in this dump, along with calculating what the full and un-truncated dump file would have been (approximately) sized at and reporting that at the end of the output run.

Links / references