### Pull Request Checklist
This PR add support for hcaptcha.com as an alternative to Google
ReCaptcha. It also makes possible for user to customize ReCaptcha URL
when needed. (Such as use recaptcha.net instead of www.google.com)
This feature needs manual test cuz it involves 3rd party _captcha_.
Signed-off-by: `Simon Ding <dxl@plotbridge.com>`
Co-authored-by: dxl <dxl@plotbridge.com>
* Remember parameters for sessions
Cleanup sessions on successfully registering or after a while
* Add flakey test
* Update to use time.AfterFunc, add more tests
* Try to drain the channel, if possible
* Initial pass at refactoring config (not finished)
* Don't forget current state and EDU servers
* More shifting around
* Update server key API tests
* Fix roomserver test
* Fix more tests
* Further tweaks
* Fix current state server test (sort of)
* Maybe fix appservices
* Fix client API test
* Include database connection string in database options
* Fix sync API build
* Update config test
* Fix unit tests
* Fix federation sender build
* Fix gobind build
* Set Listen address for all services in HTTP monolith mode
* Validate config, reinstate appservice derived in directory, tweaks
* Tweak federation API test
* Set MaxOpenConnections/MaxIdleConnections to previous values
* Update generate-config
* Pass cfg by reference around the codebase
* Merge branch 'master' into pass-cfg-by-ref
Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
