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_test.go

@@ -66,4 +66,11 @@ func TestImageExistsLocally(t *testing.T) {
 	wrongPlatform, err := ImageExistsLocally(ctx, amd64Ref, "linux/arm64")
 	assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
 	assert.False(t, wrongPlatform)
+
+	removed, err := RemoveImage(ctx, amd64Ref, false, false)
+	require.NoError(t, err)
+	assert.True(t, removed)
+	removed, err = RemoveImage(ctx, amd64Ref, false, false)
+	require.NoError(t, err)
+	assert.False(t, removed)
 }