release: add new udev rules for mounting CD-ROMs

[etungsten]

Issue number:
Fixes #1427

Description of changes:

Author: Erikson Tung <etung@amazon.com>
Date:   Wed Apr 14 17:03:22 2021 -0700

    release: add new udev rules for mounting cdroms
    
    Adds new udev rules for activating the media-cdrom.mount unit whenever
    we detect media in the CD drive. Removes `WantedBy=` from the mount unit
    as it's no longer needed.

Testing done:
Build OVA and created VM in vSphere.

Booting the VM with a CD-Drive connected with datastore stored on a CD-ROM works as expected. The CD-ROM gets mounted correctly, early-boot-config is able to read user-data from it.:

If I remove the CD-ROM from the CD-drive afterwards, the media-cdrom.mount goes inactive as does dev-cdrom.device:

Next, if I boot the VM with no CD-ROM in the drive. The host comes up fine with both media-cdrom.mount and dev-cdrom.device inactive. If I insert a CD-ROM afterwards, they become active as expected and the CD-ROM is mounted successfully at /media/cdrom.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[zmrow]

🎉

Nice work!!