Move function-p&t from upbound to crossplane-contrib

[djeremiah]

Description of your changes

The Upbound fork of function-patch-and-transform has been retired. This PR moves the composition to the crossplane-contrib repository

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

• Run make render to confirm the composition renders correctly

[haarchri]

/test-examples

[humoflife]

/test-examples

[humoflife]

Uptest failed in the resource deletion step after 1+ hour.

[haarchri]

@humoflife looks like an problem with ordered deletion:

- apiVersion: generic.vault.upbound.io/v1alpha1
  kind: Endpoint
[...]
    conditions:
    - lastTransitionTime: "2024-02-16T15:58:17Z"
      reason: Deleting
      status: "False"
      type: Ready
    - lastTransitionTime: "2024-02-16T16:00:10Z"
      message: 'connect failed: cannot get terraform setup: cannot extract credentials:
        cannot get credentials secret: Secret "vault-creds" not found'
      reason: ReconcileError
      status: "False"
      type: Synced

- apiVersion: auth.vault.upbound.io/v1alpha1
  kind: Backend
[...]
    conditions:
    - lastTransitionTime: "2024-02-16T15:58:18Z"
      reason: Available
      status: "True"
      type: Ready
    - lastTransitionTime: "2024-02-16T16:08:18Z"
      message: 'connect failed: cannot get terraform setup: cannot extract credentials:
        cannot get credentials secret: Secret "vault-creds" not found'
      reason: ReconcileError
      status: "False"
      type: Synced

[humoflife]

Closing because of another PR that moves the functions.