[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/rest/dns.go

@@ -0,0 +1,124 @@
+package rest
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+
+	"github.com/netbirdio/netbird/management/server/http/api"
+)
+
+// DNSAPI APIs for DNS Management, do not use directly
+type DNSAPI struct {
+	c *Client
+}
+
+// ListNameserverGroups list all nameserver groups
+// See more: https://docs.netbird.io/api/resources/dns#list-all-nameserver-groups
+func (a *DNSAPI) ListNameserverGroups(ctx context.Context) ([]api.NameserverGroup, error) {
+	resp, err := a.c.NewRequest(ctx, "GET", "/api/dns/nameservers", nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[[]api.NameserverGroup](resp)
+	return ret, err
+}
+
+// GetNameserverGroup get nameserver group info
+// See more: https://docs.netbird.io/api/resources/dns#retrieve-a-nameserver-group
+func (a *DNSAPI) GetNameserverGroup(ctx context.Context, nameserverGroupID string) (*api.NameserverGroup, error) {
+	resp, err := a.c.NewRequest(ctx, "GET", "/api/dns/nameservers/"+nameserverGroupID, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[api.NameserverGroup](resp)
+	return &ret, err
+}
+
+// CreateNameserverGroup create new nameserver group
+// See more: https://docs.netbird.io/api/resources/dns#create-a-nameserver-group
+func (a *DNSAPI) CreateNameserverGroup(ctx context.Context, request api.PostApiDnsNameserversJSONRequestBody) (*api.NameserverGroup, error) {
+	requestBytes, err := json.Marshal(request)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := a.c.NewRequest(ctx, "POST", "/api/dns/nameservers", bytes.NewReader(requestBytes), nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[api.NameserverGroup](resp)
+	return &ret, err
+}
+
+// UpdateNameserverGroup update nameserver group info
+// See more: https://docs.netbird.io/api/resources/dns#update-a-nameserver-group
+func (a *DNSAPI) UpdateNameserverGroup(ctx context.Context, nameserverGroupID string, request api.PutApiDnsNameserversNsgroupIdJSONRequestBody) (*api.NameserverGroup, error) {
+	requestBytes, err := json.Marshal(request)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := a.c.NewRequest(ctx, "PUT", "/api/dns/nameservers/"+nameserverGroupID, bytes.NewReader(requestBytes), nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[api.NameserverGroup](resp)
+	return &ret, err
+}
+
+// DeleteNameserverGroup delete nameserver group
+// See more: https://docs.netbird.io/api/resources/dns#delete-a-nameserver-group
+func (a *DNSAPI) DeleteNameserverGroup(ctx context.Context, nameserverGroupID string) error {
+	resp, err := a.c.NewRequest(ctx, "DELETE", "/api/dns/nameservers/"+nameserverGroupID, nil, nil)
+	if err != nil {
+		return err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+
+	return nil
+}
+
+// GetSettings get DNS settings
+// See more: https://docs.netbird.io/api/resources/dns#retrieve-dns-settings
+func (a *DNSAPI) GetSettings(ctx context.Context) (*api.DNSSettings, error) {
+	resp, err := a.c.NewRequest(ctx, "GET", "/api/dns/settings", nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[api.DNSSettings](resp)
+	return &ret, err
+}
+
+// UpdateSettings update DNS settings
+// See more: https://docs.netbird.io/api/resources/dns#update-dns-settings
+func (a *DNSAPI) UpdateSettings(ctx context.Context, request api.PutApiDnsSettingsJSONRequestBody) (*api.DNSSettings, error) {
+	requestBytes, err := json.Marshal(request)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := a.c.NewRequest(ctx, "PUT", "/api/dns/settings", bytes.NewReader(requestBytes), nil)
+	if err != nil {
+		return nil, err
+	}
+	if resp.Body != nil {
+		defer resp.Body.Close()
+	}
+	ret, err := parseResponse[api.DNSSettings](resp)
+	return &ret, err
+}