Add Azure Spring Apps Standard tier

Add Spring Apps Standard tier:
- Add bicep template in `core/host` to deploy `AI Shopping Cart Service` to Azure Spring Apps standard tier
- Name of the bicep template: `spring-apps-standard.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 Standard, the Azure Container Apps environment should not be deployed and the front-end should be deploy to Azure Static Web Apps.
- A new YAML file standard should be available to deploy the front-end to static web app. This YAML file should be rename to azure.yaml if the standard plan needs to be use
- A new `README_standard.md` should be available at the root of the repository
- In the root `README.md`/Application Architecture, a link to the standard 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_standard.md`
- A new Azure DevOps pipeline and a new GitHub workflow should be created for the standard 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
> Sample application can be deployed to Azure Spring Apps standard

### Versions
> 1.0.0

### Mention any other details that might be useful

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

Revisa los archivos de deployment existentes en core/host y main.bicep y, después, compara el README actual con la automatización del deployment. Añade la plantilla del plan Standard, el parámetro de selección, la configuración de Static Web Apps, la documentación, el pipeline de Azure DevOps y el workflow de GitHub descritos en el issue. El trabajo estará terminado cuando el ejemplo se implemente en Azure Spring Apps Standard sin implementar Container Apps y la configuración esté documentada.

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