WiredTiger key/page size configuration

The WiredTiger configuration is using small page sizes (4KB) with a relatively large default key/value size (550B). This is a bad idea; further, when larger key/value pair sizes are configured, the page/item sizes aren't adapted to match the larger key sizes.

The issue names no files, tests, or entry points. Start by locating the WiredTiger configuration and its key/value, page, and item-size settings, then compare the defaults with configurations using larger key/value pairs. Done means the relevant page and item sizes are adapted consistently and the benchmark still runs with those configurations.

Written by the indexing model from the issue text.