Continued: (please cherry-pick)

Continued: (please cherry-pick)
- rewrote fetching context parameter with protected methods to have this code encapsulated
- used this for feature controller
- added new user password-change controller (+ interface) to change user's password
- used it in template to avoid monolithic super controllers ...
- added missing i18n strings
- used password-change event for updating user's password history
- added new context parameter for "change_user_password" feature
- added new context parameter for maximum checked passwords
- fixed redirect outcomes

Signed-off-by: Roland Häder <roland@mxchange.org>