WebSecurityConfigurerAdapter is deprecated

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

### Minimal steps to reproduce
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### Any log messages given by the failure
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### Expected/desired behavior
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### OS and Version?
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### Versions
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### Mention any other details that might be useful
WebSecurityConfigurerAdapter (and therefore AadWebsecurityConfigurerAdapter) is deprecated. Vast majority of current configuration examples for spring boot are outdated and make it difficult to reconcile with latest spring boot version. Please update here as well as on the Microsoft dev guides.
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