test: db: fix test to have a smaller timeout for when it runs on faster hardware
rocksdb: Modify Block constructor to take an rvalue reference, and use std::move
rocksdb: add BlocksContents to the Block class
Move BlockContents into the Block on construct
Implement move semantics in OwnPrefixesContents
add a unique_ptr to BlockContents
rocksdb: tests: block_test: Use reference in CheckBlockContents
Cleanup some missed re-use of moved objects
Remove unused own_prefixes_contents_