Add Vendordata to metadata

[displague]

Description

Adds a vendordata key to the metadata structure. This will be used by tinkerbell/hegel#62

Why is this needed

How Has This Been Tested?

How are existing users impacted? What migration steps/scripts do we need?

The addition of a vendordata path will allow for differentiation between "userdata" and "vendordata" as described in https://cloudinit.readthedocs.io/en/latest/topics/vendordata.html

Checklist:

I have:

• updated the documentation and/or roadmap (if required)
• added unit or e2e tests
• provided instructions on how to upgrade

[codecov]

Codecov Report

Merging #579 (557dc0c) into main (1618650) will increase coverage by 0.09%.
The diff coverage is n/a.

❗ Current head 557dc0c differs from pull request most recent head 5ed656b. Consider uploading reports for the commit 5ed656b to get more accurate results

@@            Coverage Diff             @@
##             main     #579      +/-   ##
==========================================
+ Coverage   44.43%   44.52%   +0.09%     
==========================================
  Files          61       61              
  Lines        3497     3519      +22     
==========================================
+ Hits         1554     1567      +13     
- Misses       1862     1870       +8     
- Partials       81       82       +1     

Impacted Files	Coverage Δ
pkg/apis/core/v1alpha1/hardware_types.go	100.00% <ø> (ø)
pkg/controllers/workflow/controller.go	73.68% <0.00%> (-2.51%)	⬇️
server/dbserver_worker_workflow.go	89.92% <0.00%> (-1.44%)	⬇️
server/kubernetes_api_workflow.go	29.00% <0.00%> (-0.23%)	⬇️
pkg/apis/core/v1alpha1/workflow_methods.go	76.27% <0.00%> (+1.27%)	⬆️

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[jacobweinstock]

@chrisdoherty4, mind taking a look at this?

[chrisdoherty4]

This seems OK for the Kube back-end. Do we need anything in the database? Do we need a discussion around continued database support?

[chrisdoherty4]

I think we're good to merge this!

[displague]

rebased