Implemented version fetching from source control git server. Added self version detection and update checks

Moonlight.Api/Http/Controllers/Admin/VersionsController.cs

@@ -0,0 +1,46 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Moonlight.Api.Mappers;
+using Moonlight.Api.Services;
+using Moonlight.Shared;
+using Moonlight.Shared.Http.Responses.Admin;
+
+namespace Moonlight.Api.Http.Controllers.Admin;
+
+[ApiController]
+[Route("api/admin/versions")]
+[Authorize(Policy = Permissions.System.Versions)]
+public class VersionsController : Controller
+{
+    private readonly VersionService VersionService;
+
+    public VersionsController(VersionService versionService)
+    {
+        VersionService = versionService;
+    }
+
+    [HttpGet]
+    public async Task<ActionResult<VersionDto[]>> GetAsync()
+    {
+        var versions = await VersionService.GetVersionsAsync();
+        return VersionMapper.ToDtos(versions).ToArray();
+    }
+
+    [HttpGet("instance")]
+    public async Task<ActionResult<VersionDto>> GetInstanceAsync()
+    {
+        var version = await VersionService.GetInstanceVersionAsync();
+        return VersionMapper.ToDto(version);
+    }
+
+    [HttpGet("latest")]
+    public async Task<ActionResult<VersionDto>> GetLatestAsync()
+    {
+        var version = await VersionService.GetLatestVersionAsync();
+        
+        if(version == null)
+            return Problem("Unable to retrieve latest version", statusCode: 404);
+
+        return VersionMapper.ToDto(version);
+    }
+}