[misc] Move shared components to shared directory (#4286)

Moved the following directories:

```
  - management/client → shared/management/client
  - management/domain → shared/management/domain
  - management/proto → shared/management/proto
  - signal/client → shared/signal/client
  - signal/proto → shared/signal/proto
  - relay/client → shared/relay/client
  - relay/auth → shared/relay/auth
```

and adjusted import paths

shared/management/domain/list_test.go

@@ -0,0 +1,49 @@
+package domain
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_EqualReturnsTrueForIdenticalLists(t *testing.T) {
+	list1 := List{"domain1", "domain2", "domain3"}
+	list2 := List{"domain1", "domain2", "domain3"}
+
+	assert.True(t, list1.Equal(list2))
+}
+
+func Test_EqualReturnsFalseForDifferentLengths(t *testing.T) {
+	list1 := List{"domain1", "domain2"}
+	list2 := List{"domain1", "domain2", "domain3"}
+
+	assert.False(t, list1.Equal(list2))
+}
+
+func Test_EqualReturnsFalseForDifferentElements(t *testing.T) {
+	list1 := List{"domain1", "domain2", "domain3"}
+	list2 := List{"domain1", "domain4", "domain3"}
+
+	assert.False(t, list1.Equal(list2))
+}
+
+func Test_EqualReturnsTrueForUnsortedIdenticalLists(t *testing.T) {
+	list1 := List{"domain3", "domain1", "domain2"}
+	list2 := List{"domain1", "domain2", "domain3"}
+
+	assert.True(t, list1.Equal(list2))
+}
+
+func Test_EqualReturnsFalseForEmptyAndNonEmptyList(t *testing.T) {
+	list1 := List{}
+	list2 := List{"domain1"}
+
+	assert.False(t, list1.Equal(list2))
+}
+
+func Test_EqualReturnsTrueForBothEmptyLists(t *testing.T) {
+	list1 := List{}
+	list2 := List{}
+
+	assert.True(t, list1.Equal(list2))
+}