Extension [/opt/apache-druid-0.20.1/dist/druid/extensions/druid-orc-extensions] specified in “druid.extensions.loadList” didn’t exist?

I am trying to deploy apache/druid:0.20.1 in Kube. I am getting error:

`Extension [/opt/apache-druid-0.20.1/dist/druid/extensions/druid-orc-extensions] specified in "druid.extensions.loadList" didn't exist!? `

I have taken off druid-orc-extensions from extensions list in my common properties but still getting the same for the next one druid-s3-extensions and so on. I somewhere on Google found that repositoryList solved the issue. I did try:

`druid.extensions.repositoryList=[ "druid-hdfs-storage", "druid-kafka-indexing-service", "druid-datasketches","druid-s3-extensions", "druid-kafka-indexing-service", "postgresql-metadata-storage", "druid-parquet-extensions", "druid-datasketches", "druid-basic-security"]`
Now, I did not get error, but its not able to connect too Postgres Metadata and giving error:

```
2021-04-01T14:14:06,926 ERROR [main] org.apache.druid.cli.CliCoordinator - Error when starting up. Failing.
com.google.inject.ProvisionException: Unable to provision, see the following errors:
1) Unknown provider[postgresql] of Key[type=org.apache.druid.metadata.MetadataStorageProvider, annotation=[none]], known options[[derby]]
at org.apache.druid.guice.PolyBind.createChoiceWithDefault(PolyBind.java:109) (via modules: com.google.inject.util.Modules$OverrideModule -> com.google.inject.util.Modules$OverrideModule -> org.apache.druid.metadata.storage.derby.DerbyMetadataStorageDruidModule)
while locating org.apache.druid.metadata.MetadataStorageProvider
while locating org.apache.druid.metadata.MetadataStorage
```
Please suggest. Thanks.

Start with the Apache Druid 0.20.1 Kubernetes deployment and the common properties containing druid.extensions.loadList and druid.extensions.repositoryList. Trace why the ORC, S3, and PostgreSQL extensions are unavailable, then check the startup log for successful PostgreSQL metadata provider selection. Done means Druid starts and connects to the PostgreSQL metadata store without the reported errors.

Written by the indexing model from the issue text.