Support for NTLM authentication added (#109)

* Support for NTLM authentication added

To support NTLM authentication, a database is added as an authentication source.
Currently, only the configuration file is supported as a database.
Database authentication supports Basic and NTLM authentication protcols.

ServerConfig.BasicAuthEnabled renamed to LocalEnabled as Basic auth can be used with NTLM or Local.

cmd/auth/config/configuration.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"github.com/knadh/koanf/parsers/yaml"
+	"github.com/knadh/koanf/providers/confmap"
+	"github.com/knadh/koanf/providers/file"
+	"github.com/knadh/koanf/v2"
+	"log"
+	"os"
+)
+
+type Configuration struct {
+	Users    []UserConfig   `koanf:"users"`
+}
+
+type UserConfig struct {
+	Username             string   `koanf:"username"`
+	Password             string   `koanf:"password"`
+}
+
+var Conf Configuration
+
+func Load(configFile string) Configuration {
+
+	var k = koanf.New(".")
+
+	k.Load(confmap.Provider(map[string]interface{}{}, "."), nil)
+
+	if _, err := os.Stat(configFile); os.IsNotExist(err) {
+		log.Printf("Config file %s not found, skipping config file", configFile)
+	} else {
+		if err := k.Load(file.Provider(configFile), yaml.Parser()); err != nil {
+			log.Fatalf("Error loading config from file: %v", err)
+		}
+	}
+
+	koanfTag := koanf.UnmarshalConf{Tag: "koanf"}
+	k.UnmarshalWithConf("Users", &Conf.Users, koanfTag)
+
+	return Conf
+
+}