feat: ✨ added new benchmarks for comparison to manual mapping

[amyskippy]

This just adds a benchmark for comparing to a manually mapped data reader, using cast, the as methods, and the get methods. It shows that this project is faster than the cast and as methods, and comparable to doing it via the get.

I'd suggest adding the reflection benchmarks for the data reader as well, so people can do a comparison of those.

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
MapDatareader_ViaDapper	130,038.43 ns	23,380.156 ns	1,281.545 ns	7.5684	1.2207	145472 B
MapDataReader_ViaMapDataReader	145,014.83 ns	18,917.702 ns	1,036.943 ns	7.5684	1.2207	145712 B
MapDataReader_ViaManualMap_CastMethods	160,137.67 ns	3,812.999 ns	209.003 ns	7.5684	1.2207	145408 B
MapDataReader_ViaManualMap_AsMethods	212,504.85 ns	120,474.966 ns	6,603.639 ns	7.5684	1.2207	145408 B
MapDataReader_ViaManualMap_GetMethods	126,697.73 ns	25,508.688 ns	1,398.217 ns	7.5684	1.2207	145408 B