Chart: Add global.image.registry.

[Gacko]

What this PR does / why we need it:

This PR adds a global.image.registry field to the chart which makes it possible to define the registry used for pulling images across the chart in a single place.

This is useful for setups where Ingress NGINX is not getting installed as standalone but included in a different chart.

The fact that we are using the global key here makes this even easier as you only need to define it once for all the charts your including and so can reuse existing values instead of needing to change it for the Ingress NGINX chart.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• CVE Report (Scanner found CVE and adding report)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation only

How Has This Been Tested?

Added unit tests.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added unit and/or e2e tests to cover my changes.
• All new and existing tests passed.

[netlify]

✅ Deploy Preview for kubernetes-ingress-nginx canceled.

Name	Link
🔨 Latest commit	f77a947
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-ingress-nginx/deploys/66f808dfcc04560008d9075c

[Gacko]

/triage accepted
/kind feature
/priority backlog
/cc @strongjz @rikatz @tao12345666333 @cpanato

[Gacko]

/hold

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Gacko

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• charts/ingress-nginx/OWNERS [Gacko]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment