Friendly captcha throws a connection error, when site is in maintenance mode.

We should see if the external endpoint is also affected and other modules (e.g. friendly captcha) are affected as well. I'd suggest, if further captcha submodules are affected, we should introduce a setting in the parent "captcha" module. If only friendly captcha (or only the internal endpoint) is affected, we should fix it in friendly captcha.

Internal suggestion by @anybody:

_maintenance_access: Set this to TRUE to bypass the offline message and show the page normally while in maintenance mode.

I don't think any other endpoints are affected or that this is somehow related to CAPTCHA. I guess the local endpoint simply isn't accessable in maintenance mode

Here we go :)