feat(cloudflare): Support DNS record tags

[7onn]

trafficstars

What does it do ?

This will add a flags to be used on the Cloudflare provider for making comment available for DNS records.

Comment can be set as follows

• As a program flag --cloudflare-record-tags="kubernetes,external-dns"
• Or as Ingress annotations, taking precedence over the program args

annotations:
  external-dns.alpha.kubernetes.io/cloudflare-record-tags: "kubernetes,external-dns,my-app"

Motivation

That's helpful when you already have a lot of records and you'd like to track what external-dns is provisioning there and why.

Fixes #5442

More

I'll do some smoke tests in my staging envs soon! Will post the results here.

• [x] Yes, this PR title follows Conventional Commits
• [x] Yes, I added unit tests
• [ ] Yes, I updated end user documentation accordingly