Rename and refactor inventory model to bark database model

Renamed `inventoryModel.cs` to `barkDbModel.cs` and refactored the context class from `InventoryContext` to `BarkContext`. Consolidated inventory item properties into a new `InventoryItems` class for better organization and future scalability.

barkmanAPI/barkDbModel.cs

@@ -0,0 +1,35 @@
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+
+public class BarkContext : DbContext
+{
+    public DbSet<InventoryItems> Inventory  { get; set; }
+    
+    public string DbPath { get; }
+
+    public BarkContext()
+    {
+        var folder = Environment.SpecialFolder.LocalApplicationData;
+        var path = Environment.GetFolderPath(folder);
+        DbPath = System.IO.Path.Join(path, "inventory.db");
+    }
+
+    // The following configures EF to create a Sqlite database file in the
+    // special "local" folder for your platform.
+    protected override void OnConfiguring(DbContextOptionsBuilder options)
+        => options.UseSqlite($"Data Source={DbPath}");
+}
+
+public class InventoryItems
+{
+    public int Id {get; set;} 
+    public string Name { get; set; }
+    public string Brand { get; set; }
+    public string? SerialNumber { get; set; }
+    public string?  Status { get; set; }
+    public float? RentalPrice { get; set; }
+    public float? ReplacementCost { get; set; }
+    public string? Notes { get; set; }
+}
+