Membership application records with empty ('') email address - presumably after anonymization - cause unhandled exception.
AC:
- a page is being displayed that confirms the process and points out that the given data can't be displayed anymore
- The message is `Ihr Mitgliedschaftsantrag wurde erfolgreich abgeschlossen, die Bestätigungsseite kann allerdings nicht mehr angezeigt werden. Fragen zu Ihrer Mitgliedschaft können Sie uns gern per E-Mail an mitglieder@wikimedia.de stellen.`
- The e-mail address in the message is a `mailto` link
Background:
These cases can be determined by looking at the `backup` timestamp in the database record. This might not be part of the domain model, though.
```
GET /show-membership-confirmation?id=xxx&accessToken=xxx
500
[2017-12-18 07:41:56] index_php.ERROR: Given email address could not be parsed {"code":0,"file":"/usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/vendor/wmde/email-address/src/EmailAddress.php","line":21,"stack_trace":"#0 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/contexts/MembershipContext/src/DataAccess/DoctrineApplicationRepository.php(239): WMDE\\EmailAddress\\EmailAddress->__construct('')\n#1 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/contexts/MembershipContext/src/DataAccess/DoctrineApplicationRepository.php(220): WMDE\\Fundraising\\Frontend\\MembershipContext\\DataAccess\\DoctrineApplicationRepository->newApplicationDomainEntity(Object(WMDE\\Fundraising\\Entities\\MembershipApplication))\n#2 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/contexts/MembershipContext/src/Infrastructure/LoggingApplicationRepository.php(58): WMDE\\Fundraising\\Frontend\\MembershipContext\\DataAccess\\DoctrineApplicationRepository->getApplicationById(27035)\n#3 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/contexts/MembershipContext/src/UseCases/ShowMembershipApplicationConfirmation/ShowMembershipApplicationConfirmationUseCase.php(50): WMDE\\Fundraising\\Frontend\\MembershipContext\\Infrastructure\\LoggingApplicationRepository->getApplicationById(27035)\n#4 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/contexts/MembershipContext/src/UseCases/ShowMembershipApplicationConfirmation/ShowMembershipApplicationConfirmationUseCase.php(35): WMDE\\Fundraising\\Frontend\\MembershipContext\\UseCases\\ShowMembershipApplicationConfirmation\\ShowMembershipApplicationConfirmationUseCase->getMembershipApplicationById(27035)\n#5 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/app/routes.php(374): WMDE\\Fundraising\\Frontend\\MembershipContext\\UseCases\\ShowMembershipApplicationConfirmation\\ShowMembershipApplicationConfirmationUseCase->showConfirmation(Object(WMDE\\Fundraising\\Frontend\\MembershipContext\\UseCases\\ShowMembershipApplicationConfirmation\\ShowMembershipAppConfirmationRequest))\n#6 [internal function]: {closure}(Object(Symfony\\Component\\HttpFoundation\\Request))\n#7 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/vendor/symfony/http-kernel/HttpKernel.php(153): call_user_func_array(Object(Closure), Array)\n#8 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\\Component\\HttpKernel\\HttpKernel->handleRaw(Object(Symfony\\Component\\HttpFoundation\\Request), 1)\n#9 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/vendor/silex/silex/src/Silex/Application.php(496): Symfony\\Component\\HttpKernel\\HttpKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#10 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/vendor/silex/silex/src/Silex/Application.php(477): Silex\\Application->handle(Object(Symfony\\Component\\HttpFoundation\\Request))\n#11 /usr/share/nginx/www/spenden.wikimedia.de/release-20171205115907/web/index.php(89): Silex\\Application->run()\n#12 {main}"} []
```