[DOC] Add a deprecation notice to resource rancher2_pod_security_policy_template in the rancher2 docs

[markusewalker]

Is your feature request related to a problem? Please describe.

The rancher2_pod_security_policy_template resource block is what was utilized before the resource rancher2_pod_security_admission_configuration_template was created. As Rancher has migrated from PSPs to PSAs, there should be a deprecation notice with this. I do not see any such deprecation notice in the resource page.

Describe the solution you'd like

In the recent versions, 4.0.0 and above, there should be a deprecation notice that this no longer is applicable and is in favor of rancher2_pod_security_admission_configuration_template.