[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/client/mock.go

@@ -0,0 +1,95 @@
+package client
+
+import (
+	"context"
+
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+
+	"github.com/netbirdio/netbird/client/system"
+	"github.com/netbirdio/netbird/shared/management/domain"
+	"github.com/netbirdio/netbird/shared/management/proto"
+)
+
+type MockClient struct {
+	CloseFunc                      func() error
+	SyncFunc                       func(ctx context.Context, sysInfo *system.Info, msgHandler func(msg *proto.SyncResponse) error) error
+	GetServerPublicKeyFunc         func() (*wgtypes.Key, error)
+	RegisterFunc                   func(serverKey wgtypes.Key, setupKey string, jwtToken string, info *system.Info, sshKey []byte, dnsLabels domain.List) (*proto.LoginResponse, error)
+	LoginFunc                      func(serverKey wgtypes.Key, info *system.Info, sshKey []byte, dnsLabels domain.List) (*proto.LoginResponse, error)
+	GetDeviceAuthorizationFlowFunc func(serverKey wgtypes.Key) (*proto.DeviceAuthorizationFlow, error)
+	GetPKCEAuthorizationFlowFunc   func(serverKey wgtypes.Key) (*proto.PKCEAuthorizationFlow, error)
+	SyncMetaFunc                   func(sysInfo *system.Info) error
+	LogoutFunc                     func() error
+}
+
+func (m *MockClient) IsHealthy() bool {
+	return true
+}
+
+func (m *MockClient) Close() error {
+	if m.CloseFunc == nil {
+		return nil
+	}
+	return m.CloseFunc()
+}
+
+func (m *MockClient) Sync(ctx context.Context, sysInfo *system.Info, msgHandler func(msg *proto.SyncResponse) error) error {
+	if m.SyncFunc == nil {
+		return nil
+	}
+	return m.SyncFunc(ctx, sysInfo, msgHandler)
+}
+
+func (m *MockClient) GetServerPublicKey() (*wgtypes.Key, error) {
+	if m.GetServerPublicKeyFunc == nil {
+		return nil, nil
+	}
+	return m.GetServerPublicKeyFunc()
+}
+
+func (m *MockClient) Register(serverKey wgtypes.Key, setupKey string, jwtToken string, info *system.Info, sshKey []byte, dnsLabels domain.List) (*proto.LoginResponse, error) {
+	if m.RegisterFunc == nil {
+		return nil, nil
+	}
+	return m.RegisterFunc(serverKey, setupKey, jwtToken, info, sshKey, dnsLabels)
+}
+
+func (m *MockClient) Login(serverKey wgtypes.Key, info *system.Info, sshKey []byte, dnsLabels domain.List) (*proto.LoginResponse, error) {
+	if m.LoginFunc == nil {
+		return nil, nil
+	}
+	return m.LoginFunc(serverKey, info, sshKey, dnsLabels)
+}
+
+func (m *MockClient) GetDeviceAuthorizationFlow(serverKey wgtypes.Key) (*proto.DeviceAuthorizationFlow, error) {
+	if m.GetDeviceAuthorizationFlowFunc == nil {
+		return nil, nil
+	}
+	return m.GetDeviceAuthorizationFlowFunc(serverKey)
+}
+
+func (m *MockClient) GetPKCEAuthorizationFlow(serverKey wgtypes.Key) (*proto.PKCEAuthorizationFlow, error) {
+	if m.GetPKCEAuthorizationFlowFunc == nil {
+		return nil, nil
+	}
+	return m.GetPKCEAuthorizationFlow(serverKey)
+}
+
+// GetNetworkMap mock implementation of GetNetworkMap from mgm.Client interface
+func (m *MockClient) GetNetworkMap(_ *system.Info) (*proto.NetworkMap, error) {
+	return nil, nil
+}
+
+func (m *MockClient) SyncMeta(sysInfo *system.Info) error {
+	if m.SyncMetaFunc == nil {
+		return nil
+	}
+	return m.SyncMetaFunc(sysInfo)
+}
+
+func (m *MockClient) Logout() error {
+	if m.LogoutFunc == nil {
+		return nil
+	}
+	return m.LogoutFunc()
+}