[#887] node: Drop badger writecache implementation

Badger implementation isn't tested and works not well,
but requires human resources to maintain.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/writecache/generic_test.go

@@ -0,0 +1,17 @@
+package writecache
+
+import (
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/internal/storagetest"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger/test"
+)
+
+func TestGeneric(t *testing.T) {
+	storagetest.TestAll(t, func(t *testing.T) storagetest.Component {
+		return New(
+			WithLogger(test.NewLogger(t, true)),
+			WithFlushWorkersCount(2),
+			WithPath(t.TempDir()))
+	})
+}