feat: add OpenNest.Data project with MachineType and UnitSystem enums

OpenNest.Data/MachineType.cs

@@ -0,0 +1,8 @@
+namespace OpenNest.Data;
+
+public enum MachineType
+{
+    Laser,
+    Plasma,
+    Waterjet
+}

OpenNest.Data/OpenNest.Data.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net8.0-windows</TargetFramework>
+    <RootNamespace>OpenNest.Data</RootNamespace>
+    <AssemblyName>OpenNest.Data</AssemblyName>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\OpenNest.Core\OpenNest.Core.csproj" />
+  </ItemGroup>
+</Project>

OpenNest.Data/UnitSystem.cs

@@ -0,0 +1,7 @@
+namespace OpenNest.Data;
+
+public enum UnitSystem
+{
+    Inches,
+    Millimeters
+}