Add PostgreSQL server to the spire server config and get rid of using persistent volume

[denis-tingaikin]

Context

We are using persistent volumes https://github.com/networkservicemesh/deployments-k8s/pull/10287

Now we can remove it and replace PostgreSQL server configuration.

See more details ihttps://github.com/spiffe/spire/issues/1840, https://spiffe.io/docs/latest/deploying/configuring/

It could simplify the system and requirements for the customers.

Closes https://github.com/networkservicemesh/deployments-k8s/issues/11930