Declaratively setup LDAP for Grocy service

[ibizaman]

From #195 (comment)

// Either "Grocy\Middleware\DefaultAuthMiddleware", "Grocy\Middleware\ReverseProxyAuthMiddleware"
// or any class that implements Grocy\Middleware\AuthMiddleware
Setting('AUTH_CLASS', 'Grocy\Middleware\LdapAuthMiddleware');

// Options when using LdapAuthMiddleware
Setting('LDAP_ADDRESS', 'ldap://DOMAIN NAME:389'); // Example value "ldap://vm-dc2019.local.berrnd.net"
Setting('LDAP_BASE_DN', 'DC=ldap,DC=goauthentik,DC=io'); // Example value "DC=local,DC=berrnd,DC=net"
Setting('LDAP_BIND_DN', 'cn=ldapservice,ou=users,DC=ldap,DC=goauthentik,DC=io'); // Example value "CN=grocy_bind_account,OU=service_accounts,DC=local,DC=berrnd,DC=net"
Setting('LDAP_BIND_PW', 'LDAP PASSWORD'); // Password for the above account
Setting('LDAP_USER_FILTER', '(objectClass=user)'); // Example value "(OU=grocy_users)"
Setting('LDAP_UID_ATTR', 'cn'); // Windows AD: "sAMAccountName", OpenLDAP: "uid", GLAuth: "cn"