Add logging parameters for oidc-plugin

[welteki]

Description

Support configuration parameters for structured logging for the oidc-plugin in the OpenFaaS Helm chart.

Parameter	Description	Default
oidcAuthPlugin.logs.debug	Log debug messages	false
oidcAuthPlugin.logs.format	Set the log format, supports console or json	console

Why is this needed?

• I have raised an issue to propose this change (required)

Support structured logging for the oidc-plugin.

Who is this for?

What company is this for? Are you listed in the ADOPTERS.md file?

How Has This Been Tested?

Verified the log level end log encoding can be configured correctly through the Helm chart.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

The parameter oidcAuthPlugin.verbose was removed and is replaces by oidcAuthPlugin.logs.debug.

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.

[alexellis]

Approved