Remove leveldb baseline coverage gathering.
Added filter rules to remove all of the subtress (leveldb, secp256k1, ctaes, univalue) and
benchmarking from the coverage report. These items are unnecessary as we do not test for any
of the subtrees and benchmark coverage is unneeded.
Instead of using lcov -r (which is extremely slow), first use a python script to perform bulk cleanup of the /usr/include/* coverage. Then use lcov -a to remove the duplicate entries. This has the same effect of lcov -r but runs significantly faster