feat: create save new agent in db

internal/domain/agent.go

@@ -0,0 +1,27 @@
+package domain
+
+type RegisterAgentRequest struct {
+	AgentId      string
+	AgentName    string
+	AgentVersion string
+	Host         HostInfo
+	Capabilities []Capability
+}
+
+type HostInfo struct {
+	System   string
+	Hostname string
+	Arch     string
+}
+
+type Capability struct {
+	Available bool
+	Version   string
+	Name      string
+	Reason    string
+}
+
+type RegisterAgentResponse struct {
+	Heartbeat int
+	AgentID   string
+}