Adding aburden as approver; removing jobbler as reviewer

[aburdenthehand]

I would like to help out the user-guide repo by taking on the responsibility of an approver.

As per our membership policy:

• have been a reviewer on the project for more than 3 months: #753
• have reviewed ~30 PRs
• have authored 22 merged PRs

@jean-edouard and @dhiller have agreed to sponsor me.

---

I've also removed @jobbler as a reviewer, as he has not been active in this capacity for over 12 months: Thank you for all of your help in this repo over the years, John!

This PR also alphabetises the reviewer and approver owners (but not the others as these will eventually be automatically updated). (Sorry, this does make it harder to assess the changes but it didn't seem worth a second PR)

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes #

Special notes for your reviewer:

Release note:

NONE

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dhiller

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: - ~~[OWNERS](https://github.com/kubevirt/user-guide/blob/main/OWNERS)~~ [dhiller] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment