Allow mounting extra volumes to provide files that Trino might need to authenticate against external systems

[soenkeliebau]

This is a similar issue to stackabletech/druid-operator#415 and stackabletech/nifi-operator#434.

Trino may need to authenticate to backend systems that it interacts with, for example to authenticate with a kerberized HDFS we'd need to provide krb5.conf and keytab files, or as with Druid, to access GCS volumes, a google credentials file is needed.

Since Trino has a great many possible catalogs that it can connect to and this will probably grow over time, we should probably expose something very generic here to enable it - hence mounting files.

We can at a later stage always add convenience functions that automatically provision keytabs and krbconfs for a realm that is under management by us for example.