Replace ref package with k8s.io/utils/ptr

[lubronzhan]

Fix #6163

Right now k8s.io/utils/ptr implements To/Val using generics, we can just use this upstream public library

[codecov]

Codecov Report

Attention: 18 lines in your changes are missing coverage. Please review.

Comparison is base (bc89948) 81.34% compared to head (a0eaab4) 81.33%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6189      +/-   ##
==========================================
- Coverage   81.34%   81.33%   -0.01%     
==========================================
  Files         134      133       -1     
  Lines       15778    15772       -6     
==========================================
- Hits        12834    12828       -6     
  Misses       2650     2650              
  Partials      294      294              

Files	Coverage Δ
internal/contourconfig/contourconfiguration.go	98.69% <100.00%> (ø)
internal/dag/cache.go	97.03% <100.00%> (ø)
internal/dag/ingress_processor.go	98.04% <100.00%> (ø)
internal/dag/policy.go	95.52% <100.00%> (ø)
internal/gatewayapi/listeners.go	100.00% <100.00%> (ø)
internal/ingressclass/ingressclass.go	100.00% <100.00%> (ø)
internal/k8s/statusaddress.go	82.01% <100.00%> (ø)
internal/provisioner/model/model.go	100.00% <100.00%> (ø)
...nternal/provisioner/objects/dataplane/dataplane.go	87.94% <100.00%> (ø)
...ernal/provisioner/objects/deployment/deployment.go	89.90% <100.00%> (ø)
... and 6 more

[sunjayBhatia]

Some new merge conflicts from a recently merged PR but otherwise LGTM (existing package deleted + everything compiles 👍🏽)

[skriss]