feat: Adding global kedaAutoscaling section

[beatkind]

What this PR does

This PR adds a global kedaAutoscalingsection with the option to configure the prometheusAddress, pollingInterval& customHeaders.

Which issue(s) this PR fixes or relates to

Related to #7368

Checklist

• Tests updated.
• Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.

[dimitarvdimitrov]

Thanks for the PR 💪 I'm not sure about the per-component overriding, I can't think of a use case for it.

not sure how the few incorrect manifests slipped in 🤔 I checked with the original PR and everything else seems correct

[beatkind]

Thanks for the PR 💪 I'm not sure about the per-component overriding, I can't think of a use case for it.

not sure how the few incorrect manifests slipped in 🤔 I checked with the original PR and everything else seems correct

@dimitarvdimitrov I decided to remove the per component config, as you stated there will probably never be a realistic use case. And even if there would be in some edge case, this is a feature that does not need to be shipped to the majority of users. Further details of my thought process: #7392 (comment)

[dimitarvdimitrov]

nicely done! I left only one more suggestion with some docs, otherwise LGTM