Add extensions/QuickSurveys
Created by: joakin
https://gerrit.wikimedia.org/g/mediawiki/extensions/QuickSurveys
And provide a few of the different kinds of surveys in the default config in order to test them like so:
- /wiki/Test?quicksurvey=internal%20example%20survey
- /wiki/Test?quicksurvey=internal%20example%20survey%20with%20description%20and%20freeform%20text
- /wiki/Test?quicksurvey=internal%20multiple%20answer%20example%20survey%20with%20description%20and%20freeform%20text
- /wiki/Test?quicksurvey=external%20example%20survey
Fixes #338 (closed)