Remove benchmarks - Determine what to do with benchmarks

Let's discuss this between @razvan, @wlodek and @andrei. Here's my observations:

• have not been run in years
• no easy way to translate to real life parameters (like leases/sec, queries/sec etc)
• have different license (apache), which is confusing
• haven't been updated in years. For sure they don't cover DB features that's been added in recent years
• the alternative (performance tests) have gone a very long way, are very thorough and cover many real life scenarios that resonate with customer problems

Given all of the above, we should consider removing them, unless we find a good way forward how to use them effectively.