[stable/grafana] Support ingress.extraPaths for grafana

[paulopontesm]

What this PR does / why we need it:

Adding ingress.extraPaths configuration to allow users to prepend additional paths to every host. This is required when working with aws-alb-ingress-controller and configuring ssl redirection (see https://kubernetes-sigs.github.io/aws-alb-ingress-controller/guide/tasks/ssl_redirect/).

Special notes for your reviewer:

Inspired on this PR (which was not closed yet): #15080

Checklist

• DCO signed
• Chart Version bumped
• Variables are documented in the README.md
• Title of the PR starts with chart name (e.g. [stable/chart])

[k8s-ci-robot]

Hi @paulopontesm. Thanks for your PR.

I'm waiting for a helm member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[k8s-ci-robot]

@paulopontesm: GitHub didn't allow me to assign the following users: rtluckie.

Note that only helm members, repo collaborators and people who have commented on this issue/PR can be assigned. Additionally, issues/PRs can only have 10 assignees at the same time.
For more information please see the contributor guide

In response to this:

/assign @rtluckie

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[zanhsieh]

/ok-to-test
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: paulopontesm, zanhsieh

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:

• stable/grafana/OWNERS [zanhsieh]

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