README: add Build, CodeQL and OpenSSF Scorecard badges

Author: nilsbehlen

README.md

@@ -1,2 +1,7 @@
 # Java client for privacyIDEA
+
+[![Build](https://github.com/privacyidea/java-client/actions/workflows/build.yml/badge.svg)](https://github.com/privacyidea/java-client/actions/workflows/build.yml)
+[![CodeQL](https://github.com/privacyidea/java-client/actions/workflows/codeql.yml/badge.svg)](https://github.com/privacyidea/java-client/actions/workflows/codeql.yml)
+[![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/privacyidea/java-client/badge)](https://scorecard.dev/viewer/?uri=github.com/privacyidea/java-client)
+
 Java client to aid develop plugins for the privacyIDEA authentication server.