Add Azure Spring Apps Enterprise tier

Add Spring Apps Enterprisetier:
- Add bicep template in `core/host` to deploy `AI Shopping Cart Service` to Azure Spring Apps Enterprise tier
- Name of the bicep template: `spring-apps-enterprise.bicep`
- Add a parameter in `main.bicep` to select Spring Apps plan.
- Parameter name: `springAppsPlan`
- Parameter allowed values: `Consumption`, `Standard`, `Enterprise`
- Default value: `Consumption`
- When the value of `springAppsPlan` is Enterprise, the Azure Container Apps environment should not be deployed and the front-end should be deploy to Azure Spring Apps.
- A new YAML file `_enterprise` should be available to deploy the front-end to static web app. This YAML file should be rename to azure.yaml if the enterprise plan needs to be use
- A new `README_enterprise.md` should be available at the root of the repository
- In the root `README.md`/Application Architecture, a link to the enterprise tier readme should be added.
- The setup of the options (environment variable) to choose the plan needs to be described at the end of the quickstart guide and point also to `README_enterprise.md`
- A new Azure DevOps pipeline and a new GitHub workflow should be created for the enterprise plan

> Please provide us with the following information:
> ---------------------------------------------------------------

### This issue is for a: (mark with an `x`)
```
- [ ] bug report -> please search issues before submitting
- [x] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
> N/A

### Any log messages given by the failure
> N/A

### Expected/desired behavior
> Be able to deploy to Spring Apps Enterprise tier

### Versions
> 1.0.0

### Mention any other details that might be useful

> ---------------------------------------------------------------
> Thanks! We'll be in touch soon.

まず、core/host と main.bicep にある既存のデプロイフローを確認します。現在の Spring Apps プランとフロントエンドのデプロイがどのように選択されるかも確認してください。次に、Enterprise template、deployment YAML、ドキュメント、Azure DevOps pipeline、GitHub workflow を追加する前に、リポジトリの README と quickstart ガイダンスを確認します。完了条件は、Enterprise が Azure Spring Apps を選択し、Container Apps 環境を使用せず、すべてのデプロイおよびドキュメントのパスが説明されていることです。

索引モデルが issue の本文から書いたものです。