feat: support disk usage command in talosctl

Usage example:

```bash
talosctl du --nodes 10.5.0.2 /var -H -d 2
NODE       NAME
10.5.0.2   8.4 kB   etc
10.5.0.2   1.3 GB   lib
10.5.0.2   16 MB    log
10.5.0.2   25 kB    run
10.5.0.2   4.1 kB   tmp
10.5.0.2   1.3 GB   .
```

Supported flags:
- `-a` writes counts for all files, not just directories.
- `-d` recursion depth
- '-H' humanize size outputs.
- '-t' size threshold (skip files if < size or > size).

Fixes: https://github.com/talos-systems/talos/issues/2504

Signed-off-by: Artem Chernyshev <artem.0xD2@gmail.com>

internal/integration/api/diskusage.go

@@ -0,0 +1,135 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build integration_api
+
+package api
+
+import (
+	"context"
+	"io"
+	"time"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"github.com/talos-systems/talos/internal/integration/base"
+	machineapi "github.com/talos-systems/talos/pkg/machinery/api/machine"
+	"github.com/talos-systems/talos/pkg/machinery/client"
+)
+
+// DiskUsageSuite verifies Logs API.
+type DiskUsageSuite struct {
+	base.APISuite
+
+	ctx       context.Context
+	ctxCancel context.CancelFunc
+
+	nodeCtx context.Context
+}
+
+// SuiteName ...
+func (suite *DiskUsageSuite) SuiteName() string {
+	return "api.DiskUsageSuite"
+}
+
+// SetupTest ...
+func (suite *DiskUsageSuite) SetupTest() {
+	// make sure API calls have timeout
+	suite.ctx, suite.ctxCancel = context.WithTimeout(context.Background(), 2*time.Minute)
+
+	suite.nodeCtx = client.WithNodes(suite.ctx, suite.RandomDiscoveredNode())
+}
+
+// TearDownTest ...
+func (suite *DiskUsageSuite) TearDownTest() {
+	if suite.ctxCancel != nil {
+		suite.ctxCancel()
+	}
+}
+
+// TestDiskUsageRequests compares results of disk usage requests with different parameters.
+func (suite *DiskUsageSuite) TestDiskUsageRequests() {
+	type testParams struct {
+		recursionDepth int32
+		all            bool
+		paths          []string
+	}
+
+	defaultPaths := []string{
+		"/etc",
+		"/bin",
+	}
+
+	cases := []*testParams{
+		&testParams{
+			recursionDepth: 0,
+			all:            false,
+			paths:          defaultPaths,
+		},
+		&testParams{
+			recursionDepth: 1,
+			all:            false,
+			paths:          defaultPaths,
+		},
+		&testParams{
+			recursionDepth: 0,
+			all:            true,
+			paths:          defaultPaths,
+		},
+		&testParams{
+			recursionDepth: 1,
+			all:            true,
+			paths:          defaultPaths,
+		},
+		&testParams{
+			recursionDepth: 0,
+			all:            true,
+			paths:          append([]string{"/this/is/going/to/fail"}, defaultPaths...),
+		},
+	}
+
+	sizes := map[string]int64{}
+
+	for _, params := range cases {
+
+		lookupPaths := map[string]bool{}
+		for _, path := range params.paths {
+			lookupPaths[path] = true
+		}
+
+		stream, err := suite.Client.DiskUsage(
+			suite.nodeCtx,
+			&machineapi.DiskUsageRequest{
+				Paths:          params.paths,
+				RecursionDepth: params.recursionDepth,
+				All:            params.all,
+			},
+		)
+		suite.Require().NoError(err)
+
+		responseCount := 0
+		for {
+			info, err := stream.Recv()
+			responseCount++
+			if err != nil {
+				if err == io.EOF || status.Code(err) == codes.Canceled {
+					break
+				}
+
+				suite.Require().NoError(err)
+			}
+			if size, ok := sizes[info.Name]; ok {
+				suite.Require().EqualValues(size, info.Size)
+			}
+
+			sizes[info.Name] = info.Size
+		}
+		suite.Require().Greater(responseCount, 1)
+	}
+}
+
+func init() {
+	allSuites = append(allSuites, new(DiskUsageSuite))
+}