This PR adds the initial work to implement a password policy as defined in #1538.
Specifically, this implements the following
* Rate limiting for the login handler
* Implementing the ability for system admins to require a user to reset their password
* Implementing a password policy that requires passwords to be a minimum of 8 characters
* Removes the default password (gophish) for admin users to instead have the password randomly generated when Gophish first starts up
* Adds a password strength meter when choosing a new password
Fixes#1538
This builds on the work from @c-f in #1090 to fully add support for "timed" campaigns, in which the emails are spaced apart as opposed to all being sent at once.
Added the modified_date field to results so it's easy to keep track of the last results that were modified without having to parse every event. Updated the tests to reflect the changes.
Adds the capability to report phishing campaigns using an email client extension.
**Note: Gophish does not currently provide an email client extension out of the box. This is simply a mechanism to let existing email client add-ons send report status information to Gophish, and have that information reflected in the dashboard.**
