migrate to new ReCaptchta API

[Robert Jäschke]

This requires the implementation of the new API interface. The cleanest solution seems to be to implement a new library that uses the same interfaces than the existing recaptcha library we use. This would allow to easily integrate the new version into the existing code. Hence, please start to have a look at the existing recaptcha library.

Details about the new API can be obtained from the senior developers.

[Robert Jäschke]

Please discuss with me in the next meeting how to start the implementation.

[Thomas Niebler]

Should be working now. The old API keys still work for the new ReCaptcha2 API.

[Daniel Zoller]

adapt error message (still Please enter the displayed words into the form.)

[Daniel Zoller]

thx you!!