[fixmystreet.com] Add option for recaptcha.

[dracos]

This shows a recaptcha to logged out users from non-UK IP addresses on alert and report/update forms. For https://github.com/mysociety/sysadmin/issues/1302.

[codecov]

Codecov Report

Merging #3050 into master will increase coverage by 0.00%.
The diff coverage is 85.71%.

@@           Coverage Diff           @@
##           master    #3050   +/-   ##
=======================================
  Coverage   83.13%   83.14%           
=======================================
  Files         246      246           
  Lines       15430    15451   +21     
  Branches     2879     2886    +7     
=======================================
+ Hits        12827    12846   +19     
  Misses       1690     1690           
- Partials      913      915    +2     

Impacted Files	Coverage Δ
perllib/FixMyStreet/Gaze.pm	40.00% <66.66%> (+6.66%)	⬆️
perllib/FixMyStreet/Cobrand/UK.pm	75.26% <86.66%> (+0.97%)	⬆️
perllib/FixMyStreet/App.pm	87.91% <100.00%> (+0.16%)	⬆️
perllib/FixMyStreet/App/Controller/Auth.pm	84.32% <100.00%> (+0.05%)	⬆️
perllib/Utils.pm	98.98% <0.00%> (+1.01%)	⬆️

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[chrismytton]

Code looking good!

Would it be possible to add a test to check that the <div class="g-recaptcha" /> element is on the page when the user's IP is non-GB?

Can we also add some documentation for RECAPTCHA config? I tried to get this working but wasn't sure what config I needed or where to get it from?

Would also be good to add a changelog entry for this 🙂

[chrismytton]

Oh and there are quite a few red crosses in the checks section. Would be good to reduce those a bit!

[chrismytton]

🧩

[sagepe]

🎸