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/database/config.go

@@ -0,0 +1,25 @@
+package database
+
+import (
+	"github.com/bolkedebruin/rdpgw/cmd/auth/config"
+)
+
+type Config struct {
+	users map[string]config.UserConfig
+}
+
+func NewConfig(users []config.UserConfig) *Config {
+        usersMap := map[string]config.UserConfig{}
+                
+        for _, user := range users {
+                usersMap[user.Username] = user
+        }
+        
+	return &Config{
+		users: usersMap,
+	}
+}
+
+func (c *Config) GetPassword (username string) string {
+        return c.users[username].Password
+}