Having a user set a language is broken

Background

In the Reference Application, you can set the user's default locale from My Account -> Default Settings, however (a) sometimes this leads to a broken page, and (b) this does not actually have any effect.

(a) is inconsistent, and I haven't figured out why, but has its own ticket as RA-992

(b) happens consistently

Also, ticket RA-995 is about improving the user experience of this workflow, so if that ticket has been done already, then the look and feel won't exactly match what is written on this ticket.

Dev Notes

• The bug is in https://github.com/openmrs/openmrs-module-referenceapplication/blob/master/omod/src/main/java/org/openmrs/module/referenceapplication/page/controller/LoginPageController.java
• PIH's code for Mirebalais does this correctly, so you can probably copy a code snippet from https://github.com/PIH/openmrs-module-mirebalais/blob/master/omod/src/main/java/org/openmrs/module/mirebalais/page/controller/LoginPageController.java

Acceptance Criteria

1. When I go to My Account -> Default Settings and change my Default Locale, log out, and log in again, then I should see the UI translated into my selected language.