Supports use of extra credentials

[shawnzhu]

Background

I raised the question anyway to support session level connector configuration for presto on stackoverflow to see if it can support scenario like two different presto users can use their own connector level credential. This answer pointed me to the class io.prestosql.plugin.jdbc.credential.ExtraCredentialProvider where the idea extra credential is.

Also see trinodb/trino#1910 for more context.

Plan

Will try to make it happen and document it.