[#760] Added new page for changing passwords in MyRSR

No link to the password changing page is included on the main page of MyRSR yet, but page can be visited at ../myrsr/password_change
[#761] Draft version of Ajax post requests on MyRSR page

First implementation of the Ajax post requests. There's still work to do on the UI part, e.g.:
- How (long) do we show notifications of a success or fail?
- Add a loading icon when an Ajax call is in process
[#760] Updated change password page

The change password page has been updated, now using an AJAX call and giving feedback. However, same as for the other AJAX calls, the UI and UX still need improving.
Merge pull request #762 from akvo/feature/760_password_page

[#760] Added new page for changing passwords in MyRSR
[#761] Removed AJAX test view
[#761] Fix conflicts
Merge branch 'feature/761_ajax_controls' into feature/rsr_v3
Merge branch 'feature/rsr_v3' of https://github.com/akvo/akvo-rsr into feature/759_myrsr_templates
[#759] CSS updates to template