planetfm: TM-152: migrate training env to network LB

[drobinson-moj]

This has been tested by Glenn - now make it live. Hardly anyone using training right now so has minimal impact.

[github-actions]

Trivy Scan Success

Show Output

```hcl

---

Trivy will check the following folders:
terraform/environments/planetfm

---

Running Trivy in terraform/environments/planetfm
2024-09-03T14:04:39Z INFO [db] Need to update DB
2024-09-03T14:04:39Z INFO [db] Downloading DB... repository="ghcr.io/aquasecurity/trivy-db:2"
2024-09-03T14:04:41Z INFO [vuln] Vulnerability scanning is enabled
2024-09-03T14:04:41Z INFO [misconfig] Misconfiguration scanning is enabled
2024-09-03T14:04:41Z INFO Need to update the built-in policies
2024-09-03T14:04:41Z INFO Downloading the built-in policies...
74.86 KiB / 74.86 KiB [-----------------------------------------------------------] 100.00% ? p/s 0s2024-09-03T14:04:41Z INFO [secret] Secret scanning is enabled
2024-09-03T14:04:41Z INFO [secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-09-03T14:04:41Z INFO [secret] Please see also https://aquasecurity.github.io/trivy/v0.54/docs/scanner/secret#recommendation for faster secret detection
2024-09-03T14:04:44Z INFO Number of language-specific files num=0
2024-09-03T14:04:44Z INFO Detected config files num=7
trivy_exitcode=0

</details> #### `Checkov Scan` Success
<details><summary>Show Output</summary>

```hcl

*****************************

Checkov will check the following folders:
terraform/environments/planetfm

*****************************

Running Checkov in terraform/environments/planetfm
Excluding the following checks: CKV_GIT_1,CKV_AWS_126,CKV2_AWS_38,CKV2_AWS_39
terraform scan results:

Passed checks: 137, Failed checks: 0, Skipped checks: 24


checkov_exitcode=0

CTFLint Scan Success

Show Output

*****************************

Setting default tflint config...
Running tflint --init...
Installing "terraform" plugin...
Installed "terraform" (source: github.com/terraform-linters/tflint-ruleset-terraform, version: 0.5.0)
tflint will check the following folders:
terraform/environments/planetfm

*****************************

Running tflint in terraform/environments/planetfm
Excluding the following checks: terraform_unused_declarations
tflint_exitcode=0

Trivy Scan Success

Show Output

*****************************

Trivy will check the following folders:
terraform/environments/planetfm

*****************************

Running Trivy in terraform/environments/planetfm
2024-09-03T14:04:39Z	INFO	[db] Need to update DB
2024-09-03T14:04:39Z	INFO	[db] Downloading DB...	repository="ghcr.io/aquasecurity/trivy-db:2"
2024-09-03T14:04:41Z	INFO	[vuln] Vulnerability scanning is enabled
2024-09-03T14:04:41Z	INFO	[misconfig] Misconfiguration scanning is enabled
2024-09-03T14:04:41Z	INFO	Need to update the built-in policies
2024-09-03T14:04:41Z	INFO	Downloading the built-in policies...
74.86 KiB / 74.86 KiB [-----------------------------------------------------------] 100.00% ? p/s 0s2024-09-03T14:04:41Z	INFO	[secret] Secret scanning is enabled
2024-09-03T14:04:41Z	INFO	[secret] If your scanning is slow, please try '--scanners vuln' to disable secret scanning
2024-09-03T14:04:41Z	INFO	[secret] Please see also https://aquasecurity.github.io/trivy/v0.54/docs/scanner/secret#recommendation for faster secret detection
2024-09-03T14:04:44Z	INFO	Number of language-specific files	num=0
2024-09-03T14:04:44Z	INFO	Detected config files	num=7
trivy_exitcode=0