FoundationDB performance comparison for Voron

Using FoundationDB C# Client from here : https://github.com/Doxense/foundationdb-dotnet-client
(This is included in the PR).

It will compile as-is, but to run it you must;

1. Install FoundationDB for windows from https://foundationdb.com/get
2. Copy the contents of C:\ProgramData\foundationdb\fdb.cluster into the same file in the project folder (this is like a connection string file)

I couldn't perform a comparison myself as Voron kept crashing with AccessViolationException on my machine...