feat(ai-server): use env variables for the cpu and memory of the task

[y3rsh]

Use variables for cpu and memory

Note

It is easy to increase the number of tasks running in a given cluster with the AWS console so we won't automate that part now.

• Add cpu and memory to settings and use the value at task definition creation
• Update dev env variables secret
• Update prod env variables secret

Once merged

1. see that staging has the correct values.
2. tag and see the prod deployment has the correct values.

[shlokamin]

lgtm