Add cloud-init metadata option

[rolffujino]

/kind feature

Describe the solution you'd like
Please add an option to inject cloud-init metadata, similar to that of user_data option:

Anything else you would like to add:
It is already available in the API v3 from Nutanix, so should be available here as well.

Environment:

• packer-plugin-nutanix version (use packer plugins installed): packer-plugin-nutanix_v0.8.1_x5.0_linux_amd64
• Packer version (use packer version): Packer v1.9.4
• OS (e.g. from /etc/os-release): 22.04.2 LTS (Jammy Jellyfish)

[tuxtof]

hello @rolffujino , in this case if you want to provide both metadata and user-data by yourself
why don't you take the approach to generate the cloud-init cd on the fly with packer ?

you can use the cd_files and cd_label option to do that

longterm we can think to add a such feature , just need to take care about the metadata uuid