Add benchmarks project

[lahma]

This PR adds a new benchmark project which utilizes BenchmarkDotNet for precise and repeatable results. I adjusted test cases from this blog post to create presentation of areas.

I have diff tools that I can use to show performance changes between master and proposed optimization.

You can run the benchmarks by simply running the benchmarks project using Release configuration. It will as what benchmark(s) to run.

My first PR will tackle the LargeExcelFileBenchmark.Evaluate which is obviously the worst case at the moment as it takes over a minute to complete on my desktop.

Current results

BenchmarkDotNet=v0.13.5, OS=Windows 11 (10.0.23466.1001)
AMD Ryzen 9 5950X, 1 CPU, 32 logical and 16 physical cores
.NET SDK=7.0.302
  [Host]   : .NET 6.0.16 (6.0.1623.17311), X64 RyuJIT AVX2
  ShortRun : .NET 6.0.16 (6.0.1623.17311), X64 RyuJIT AVX2

Job=ShortRun  IterationCount=3  LaunchCount=1  
WarmupCount=3  

NPOI.Benchmarks.LargeExcelFileBenchmark

Method	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
Load	11.741 s	1.1257 s	0.0617 s	232000.0000	109000.0000	3000.0000	3.65 GB
Write	3.483 s	0.1738 s	0.0095 s	44000.0000	-	-	1.19 GB
Evaluate	62.677 s	4.1891 s	0.2296 s	4810000.0000	1353000.0000	-	75.32 GB

NPOI.Benchmarks.RangeValuesBenchmark

Method	RowCount	ColumnCount	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
Double	1000	30	85.46 ms	0.367 ms	0.343 ms	2000.0000	1000.0000	500.0000	31.45 MB
String	1000	30	99.93 ms	0.449 ms	0.420 ms	4400.0000	2000.0000	1000.0000	59.32 MB
Date	1000	30	114.71 ms	1.603 ms	1.499 ms	3000.0000	2000.0000	1200.0000	35.73 MB
Formulas	1000	30	1,064.12 ms	10.889 ms	9.653 ms	94000.0000	27000.0000	4000.0000	1480.15 MB

[tonyqus]

LGTM