Fix connection timeout error, add example

This fixes an issue where the LDAP connection can timeout/get closed by the LDAP server due to idle time which will break the Strategy from working unless the application is restarted.

Adds the ability to configure the username/password field to use from the request, and adds support for replacing the placeholder string in the configured filter. (#7)

I've also added a Windows LDAP example. (#4)


Tested with a Windows AD server