Delete crossplane.yaml

[jahabibi]

Remove crossplane yaml in favor of Upbound yaml and Upbound Devex

Description of your changes

Removing legacy crossplane.yaml since this has been migrated to an Upbound Configuration.

Fixes #

I have:

• Read and followed Upbound's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

up project build

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