feat(data): rename *.Services projects, lift TrackEntity onto BlazorBlocks data layer, regenerate initial Postgres migration

DeepDrftWeb.Services → DeepDrftData; DeepDrftContent.Services → DeepDrftContent.Data.
TrackEntity:BaseEntity, TrackRepository:Repository<>, TrackManager:Manager<>+ITrackService.
Drops DeepDrftModels PagingParameters/PagedResult in favour of Models.Common.* from BlazorBlocks.
InitialCreate migration captures full schema including is_deleted index.

DeepDrftData/Data/DeepDrftContext.cs

@@ -0,0 +1,21 @@
+using DeepDrftModels.Entities;
+using DeepDrftData.Data.Configurations;
+using Microsoft.EntityFrameworkCore;
+
+namespace DeepDrftData.Data;
+
+public class DeepDrftContext : DbContext
+{
+    public DeepDrftContext(DbContextOptions<DeepDrftContext> options) : base(options)
+    {
+    }
+
+    public DbSet<TrackEntity> Tracks { get; set; }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.ApplyConfiguration(new TrackConfiguration());
+    }
+}