Upgrade Angular to 6.1.10 (i.e. latest): upgrade to the HttpClient.
Upgrade Angular Material to 6.4.7 (i.e. latest): upgrade to mat-*
elements, attributes and directives; fix date pickers; fix missing
md-input-containers elements.
Upgrade RxJS to 6.2.2 (i.e. latest). Remove RxJS from devDependencies.
Remove unused codelyzer dependency.
Remove no longer needed md2 dependency.
Add section for the certificate to the user screen.
Add certificate service to support uploading certificates to the server.