Update Terraform to not use deprecated resources

[simu]

Currently the OCP4 Exoscale Terraform module (and the vshn-lbaas-exoscale Terraform module) uses a bunch of resources which have been deprecated in recent releases of the Exoscale provider. Please note that some of the deprecated resources are actually broken in the latest reslease (0.40.1), e.g. I'm intermittently getting errors like with provider version 0.40.1

│ Error: failed to retrieve reverse DNS: malformed JSON response 500, "queryreversednsforpublicipaddressresponse" was expected.
│ {"errorcode":500,"cserrorcode":9999,"errortext":"Internal error. It might be temporary, try again later and/or contact <support@exoscale.com> if it persists.","uuidList":[]}
│ 
│   with module.cluster.module.lb.exoscale_ipaddress.ingress,
│   on .terraform/modules/cluster.lb/modules/vshn-lbaas-exoscale/main.tf line 35, in resource "exoscale_ipaddress" "ingress":
│   35: resource "exoscale_ipaddress" "ingress" {

We should update this module and the imported vshn-lbaas-exoscale module to ensure we only use supported resources.

Side-note: this will create a functional regression for the module, as the new floating IP resource exoscale_elastic_ip doesn't support settings the reverse DNS name yet (cf. https://github.com/exoscale/terraform-provider-exoscale/issues/188).

[simu]

Deprecated resources which are in use and their replacements:

• exoscale_ipaddress -> exoscale_elastic_ip
• exoscale_compute -> exoscale_compute_instance
• exoscale_affinity -> exoscale_anti_affinity_group
• exoscale_security_group_rules -> exoscale_security_group_rule
• exoscale_ssh_keypair -> exoscale_ssh_key

Deprecated data sources:

• exoscale_network -> exoscale_private_network

If we want to revisit the experimental private network support:

• exoscale_network -> exoscale_private_network
• exoscale_nic -> removed, can be configured in exoscale_compute_instance instead

Resources with breaking changes:

• exoscale_domain_record wants exoscale_domain.<name>.id for field domain instead of exoscale_domain.<name>.name