Added daily reminder emails to be sent as password expiration nears

[farkwun]

Current functionality really only works with Redmine 3.x, as existing code uses Setting.password_max_age, a hash key that doesn't exist in 2.x.

Compatibility attempted with some lines, but account policy as it stands likely will not work if code remains the same. Regardless, mail templates and functions created and tied into daily tasks run per day.

Also made some changes to settings page, ensure all text boxes are number boxes (excepting the password complexity box, as that should be a dropdown, not a number field at all)

[farkwun]

1

[farkwun]

Captured by #19