Add plan modifiers to stop showing values that didn't change on TF plan

[posriniv]

Today, when we run terraform plan we show all the computed attributed though they didn't change. It makes it difficult to properly identify the attributes that didn't change. Plan modifiers come to our rescue here helping us hide the computed attributes from the plan.

For example, here is the plan after changing num_cores before the change was done:

bash-5.2$ terraform plan
ybm_allow_list.mylist: Refreshing state...
ybm_cluster.single_region: Refreshing state...

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # ybm_cluster.single_region will be updated in-place
  ~ resource "ybm_cluster" "single_region" {
      ~ account_id             = "5379da8e-9248-42f4-bd25-ebd7341eae69" -> (known after apply)
      ~ backup_schedules       = [
          ~ {
              ~ backup_description       = "Default backup schedule" -> (known after apply)
              + cron_expression          = (known after apply)
              ~ schedule_id              = "d97a8d18-2d59-48f6-a7f7-5d9620ce9541" -> (known after apply)
                # (3 unchanged attributes hidden)
            },
        ]
      ~ cluster_certificate    = <<-EOT
            -----BEGIN CERTIFICATE-----
            redacted
            ------------------------------
        EOT -> (known after apply)
      ~ cluster_endpoints      = {
          - "us-west2" = "us-west2.dae29dd9-14e7-42fd-9da9-df98a1f21b62.gcp.devcloud.yugabyte.com"
        } -> (known after apply)
      ~ cluster_id             = "dae29dd9-14e7-42fd-9da9-df98a1f21b62" -> (known after apply)
      ~ cluster_info           = {
          ~ created_time     = "2025-01-29T21:36:45.425Z" -> (known after apply)
          ~ software_version = "2024.1.4.0-b108" -> (known after apply)
          ~ state            = "ACTIVE" -> (known after apply)
          ~ updated_time     = "2025-01-29T21:46:42.364Z" -> (known after apply)
        } -> (known after apply)
      ~ cluster_region_info    = [
          ~ {
              ~ disk_iops     = 0 -> (known after apply)
              ~ disk_size_gb  = 100 -> (known after apply)
              ~ is_default    = true -> (known after apply)
              ~ is_preferred  = false -> (known after apply)
              ~ num_cores     = 2 -> 4
              ~ public_access = true -> (known after apply)
              + vpc_id        = (known after apply)
              + vpc_name      = (known after apply)
                # (2 unchanged attributes hidden)
            },
        ]
      ~ cluster_version        = "8" -> (known after apply)
      ~ database_track         = "Innovation" -> (known after apply)
      ~ desired_state          = "Active" -> (known after apply)
      ~ endpoints              = [
          - {
              - accessibility_type = "PUBLIC" -> null
              - host               = "us-west2.dae29dd9-14e7-42fd-9da9-df98a1f21b62.gcp.devcloud.yugabyte.com" -> null
              - region             = "us-west2" -> null
            },
        ] -> (known after apply)
      ~ node_config            = {
          ~ disk_iops    = 0 -> (known after apply)
          ~ disk_size_gb = 100 -> (known after apply)
          ~ num_cores    = 2 -> (known after apply)
        } -> (known after apply)
      ~ num_faults_to_tolerate = 0 -> (known after apply)
      ~ project_id             = "847ad1d5-2eaa-46f5-8528-cca023d1f540" -> (known after apply)
        # (7 unchanged attributes hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Here is it after the change is done:

bash-5.2$ terraform plan
ybm_allow_list.mylist: Refreshing state...
ybm_cluster.single_region: Refreshing state...

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # ybm_cluster.single_region will be updated in-place
  ~ resource "ybm_cluster" "single_region" {
      ~ cluster_region_info    = [
          ~ {
              ~ num_cores     = 2 -> 4
                # (9 unchanged attributes hidden)
            },
        ]
        # (20 unchanged attributes hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.