[fix][fn] enable Go function token auth

[flowchartsman]

Fixes apache#20451

Motivation

Go functions die when auth is turned on. I would like them to not die.

Modifications

Added transport of auth plugin and auth plugin params to go instance config.
Added parsing of these values into the pf sdk

Verifying this change

• Make sure that the change passes the CI checks.
• Cannot integration test functions with auth

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

No doc change needed, because the docs don't mention the exception, so now the intuitive assumption holds.

Matching PR in forked repository

PR in forked repository: #6