Spam check and reCAPTCHA improvements

app/controllers/concerns/spammable_actions.rb

app/controllers/projects/issues_controller.rb

app/controllers/projects/snippets_controller.rb

app/controllers/snippets_controller.rb

app/models/concerns/spammable.rb

app/models/project_snippet.rb

app/services/create_snippet_service.rb

app/services/issuable_base_service.rb

app/services/issues/create_service.rb

app/services/issues/update_service.rb

app/services/spam_check_service.rb

app/services/spam_service.rb

app/services/update_snippet_service.rb

app/views/layouts/_recaptcha_verification.html.haml

app/views/projects/issues/verify.html.haml

app/views/projects/snippets/verify.html.haml

app/views/snippets/verify.html.haml

...unreleased/28093-snippet-and-issue-spam-check-on-edit.yml

lib/api/helpers.rb

lib/api/issues.rb