Remove ACTIONS_ACR & consolidate secrets

[tamirkamara]

What is being addressed

1. Github Actions currently use a separate ACR (aka ACTIONS_ACR) to store the devcontainer images. This requires more initial setup which confuses users.
2. We ask users to provide both AZURE_CREDENTIALS and ARM_* style secrets which are duplication

We can make this simpler...
Closes microsoft/AzureTRE-Deployment#10

Migration

1. Validate your Github environment has the AZURE_CREDENTIALS secret defined, in the following format:

{
  "clientId": "xxx",
  "clientSecret": "xxx",
  "tenantId": "xxx",
  "subscriptionId": "xxx",
"resourceManagerEndpointUrl": "management.azure.com"
}

1. Delete the following Github Secrets: ACTIONS_ACR_NAME, ACTIONS_ACR_PASSWORD, ARM_CLIENT_ID, ARM_CLIENT_SECRET, ARM_SUBSCRIPTION_ID, ARM_TENANT_ID

How is this addressed

• TRE devcontainer will be stored in the ACR defined for the environment in the ACR_NAME secret
• Change the actions so that they will "wait" for the ACR to be created for a new environment without failure. This makes it transparent for the user without any special setup required.
• Actions access the ACR via azure login (az acr login)
• Remove all ARM_* style credential secrets and fall back to using AZURE_CREDENTIALS

[github-actions]

Unit Test Results

17 tests  +12   17 ✔️ +13   6s ⏱️ - 2h 24m 39s
  1 suites ±  0     0 💤 ±  0 
  1 files   ±  0     0 ❌  -   1 

Results for commit f7d3769. ± Comparison against base commit b89a336.

This pull request removes 5 and adds 17 tests. Note that renamed tests count towards both.

test_airlock ‑ test_airlock_import_flow
test_shared_services ‑ test_create_shared_service[tre-shared-service-gitea]
test_shared_services ‑ test_patch_firewall
test_workspace_services ‑ test_create_guacamole_service_into_aad_workspace
test_workspace_services ‑ test_create_guacamole_service_into_base_workspace

test_provisioned_health_api ‑ test_health
test_shared_service_templates ‑ test_get_shared_service_template[tre-shared-service-firewall]
test_shared_service_templates ‑ test_get_shared_service_template[tre-shared-service-gitea]
test_shared_service_templates ‑ test_get_shared_service_templates[tre-shared-service-firewall]
test_shared_service_templates ‑ test_get_shared_service_templates[tre-shared-service-gitea]
test_ui ‑ test_ui
test_workspace_service_templates ‑ test_create_workspace_service_templates
test_workspace_service_templates ‑ test_get_workspace_service_template[tre-service-azureml]
test_workspace_service_templates ‑ test_get_workspace_service_template[tre-service-guacamole]
test_workspace_service_templates ‑ test_get_workspace_service_template[tre-service-innereye]
…

♻️ This comment has been updated with latest results.

[marrobi]

@tamirkamara @LizaShak the docs https://microsoft.github.io/AzureTRE/tre-admins/environment-variables/ stull reference ARM_ credentials - does this need updating?