Emulate production workload at larger scales

The workload used to test FDB's scalability is better to be as similar to a real production workload as possible.

A workload's characteristics include:
1) The statistical distributions of data stored in the disk. For example, how data is skewed. This will affect how shards are created, for example;
2) The read and write pattern;
(and more)

To emulate a production workload, we need:
- [ ] Capture the synopsis of production workload;
- [ ] Capture the workload pattern per FDB component, so that we can just test a single component instead of the entire cluster to reduce the testing cost;

[This idea was proposed and discussed in FDB Offset 2019.]

The issue names no implementation files, tests, or entry points; start by reviewing the FDB Offset 2019 discussion referenced in the issue. Define the production-workload synopsis and per-component workload patterns, and consider the work done when both checklist items are captured for larger-scale scalability testing.

Written by the indexing model from the issue text.