Add service config options to env-config

[lorenyu]

Ticket

N/A

Changes

• Add env-config settings for service CPU, memory, and desired instance count
• Set prod to 1 vCPU, 4 GB memory, and 3 instances
• Add instructions

Context

Add env-config settings for setting an environment's service's CPU, memory, and desired instance count. This allows a project to have separate settings for each environment.

Testing

Temporarily set app-config's has_database to false (so we don't need to create a prod database layer), and set prod.tf's config to set network_name to "dev" (so we don't need to create a prod VPC), then ran terraform plan for prod. Here are the relevant sections that show that desired count is 3 and that CPU and memory settings are different from the defaults:

Ran the following commands (image_tag is the current commit on main branch)

make infra-configure-app-service APP_NAME=app ENVIRONMENT=prod
TF_CLI_ARGS_apply='-var=image_tag="0b7fbe62bb7a925ffd314dae444ab3a84b968701"' make infra-update-app-service APP_NAME=app ENVIRONMENT=prod

Terraform plan screenshots:

[lorenyu]

Done in navapbc/template-infra#503