refactor: move database-related projects to separate folder

SqlData/Application/Cqrs/Group/Queries/GetGroupList/GetGroupListQueryHandler.cs

@@ -0,0 +1,31 @@
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using Mirea.Api.DataAccess.Application.Interfaces.DbContexts.Schedule;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Mirea.Api.DataAccess.Application.Cqrs.Group.Queries.GetGroupList;
+
+public class GetGroupListQueryHandler(IGroupDbContext dbContext) : IRequestHandler<GetGroupListQuery, GroupListVm>
+{
+    public async Task<GroupListVm> Handle(GetGroupListQuery request, CancellationToken cancellationToken)
+    {
+        var dtos = dbContext.Groups.OrderBy(g => g.Id).Select(g => new GroupLookupDto()
+        {
+            Id = g.Id,
+            Name = g.Name,
+            FacultyId = g.FacultyId
+        });
+
+        if (request is { PageSize: not null, Page: not null })
+            dtos = dtos.Skip(request.Page.Value * request.PageSize.Value).Take(request.PageSize.Value);
+
+        var result = await dtos.ToListAsync(cancellationToken);
+
+        return new GroupListVm
+        {
+            Groups = result
+        };
+    }
+}