Add mermaid diagram for image build + azure pool creation

[gvegayon]

I was just adding a mermaid diagram, @zsusswein. Here it is:

flowchart LR

  START((Start))---DEPS_CACHED

  DEPS_CACHED{Deps<br>cached?}---|No|DEPS
  DEPS_CACHED---|Yes|IMG

  subgraph DEPS[Job01-build_image_dependencies]
    direction TB
    Dockerfile-dependencies---|Generates|DEPS_IMAGE[Dependencies<br>Image]
  end

  DEPS---IMG

  subgraph IMG[_01_build-model-image]
    direction TB
    Dockerfile---|Generates|PKG_IMG[Package<br>Image]
  end

  IMG---POOL

  subgraph POOL[_02_create-batch-pool-and-submit-jobs]
    direction TB

    POOL_EXISTS{Is the pool<br>up?}
    POOL_EXISTS---|No|CREATE_POOL[Create the pool]
    POOL_EXISTS---|Yes|DELETE_POOL{Commit includes<br>'delete pool'}
    DELETE_POOL---END_POOL((End))
    CREATE_POOL---END_POOL

  end

If you like it, I can PR it

Originally posted by @gvegayon in https://github.com/CDCgov/cfa-epinow2-pipeline/issues/67#issuecomment-2415345451

[zsusswein]

Closed by #84