Upgrade to Quarkus 2.0

• Fixed configuration source which added a new method to implement
• Repaired the persistence extension BuildTime processor which had references to no longer existing buildstep enhancements.
• Added missing config values for Solr DAO that caused build failures with more strict default value checking.
• Added explicit creation of placeholder DB DAO for search, as the unremovable flag was ignored.

core/src/main/java/org/eclipsefoundation/core/config/SecretConfigSource.java

@@ -14,6 +14,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 import java.util.ServiceLoader;
+import java.util.Set;
 
 import org.eclipse.microprofile.config.spi.ConfigSource;
 import org.slf4j.Logger;
@@ -85,4 +86,9 @@ public class SecretConfigSource implements ConfigSource {
 	public String getName() {
 		return "secret";
 	}
+
+	@Override
+	public Set<String> getPropertyNames() {
+		return getProperties().keySet();
+	}
 }