Spring - E2E sample demonstrating interaction with AAD, externalized configurations, secret management and data persistence layer with Azure data services

[z1069867141]

Implement Toy Store
https://dev.azure.com/azure-spring-integration/spring-integration-private/_wiki/wikis/spring-integration-private.wiki?pagePath=%2FEnd%20to%20end%20samples%2FToy%20store

• Create a Spring Boot/Spring MVC E2E sample to demonstrate usage of Spring Azure modules #21474

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Related PR:Azure-Samples/azure-spring-boot-samples#45

[stliu]

@chenrujun please check the PR already existed