perf: speed up job setup, action preparation and the cache server (#1327)

- Look up containers by name instead of listing all of them
- On Linux, cache the docker proxy discovery instead of starting a probe container per job
- Download a job's actions concurrently and share identical fetches between concurrent jobs
- Cache `runner.arch` per run and poll service health every 250ms
- Cache server: queue on an in-process lock instead of polling the database file lock, upload S3 objects up to 64MiB in one request and larger ones in 4 concurrent parts

| `exec`, median of 5 | Before | After |
|---|---:|---:|
| 1 step | 1.70s | 0.87s |
| 10 steps | 2.84s | 1.97s |
| Service + step | 3.78s | 2.18s |
| checkout + Node action | 3.64s | 2.52s |

Reviewed-on: https://gitea.com/gitea/runner/pulls/1327
Reviewed-by: Zettat123 <[email protected]>

act/container/docker_images.go

@@ -58,18 +58,14 @@ func RemoveImage(ctx context.Context, imageName string, force, pruneChildren boo
 	}
 	defer cli.Close()
 
-	if _, err := cli.ImageInspect(ctx, imageName); cerrdefs.IsNotFound(err) {
+	if _, err = cli.ImageRemove(ctx, imageName, client.ImageRemoveOptions{
+		Force:         force,
+		PruneChildren: pruneChildren,
+	}); cerrdefs.IsNotFound(err) {
 		return false, nil
 	} else if err != nil {
 		return false, err
 	}
 
-	if _, err = cli.ImageRemove(ctx, imageName, client.ImageRemoveOptions{
-		Force:         force,
-		PruneChildren: pruneChildren,
-	}); err != nil {
-		return false, err
-	}
-
 	return true, nil
 }