Support structured logging config for faas-netes (Standard/Enterprise)

Description

Support configuring the log level and format for the faas-netes controller (Standard/Enterprise)

faasnetesPro:
  logs:
    debug: false
    format: "console"

Why is this needed?

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

Logs for OpenFaaS IAM where moved to the debug level. This change is required to support setting the log level when running OpenFaaS IAM with the faas-netes controller mode.

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 and format are set correctly when the chart values are updated:

kubectl logs -n openfaas deploy/gateway -c faas-netes

Types of changes

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

Checklist:

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

openfaas / faas-netes