Support "Active Directory Password" authentication method for TargetSqlConnectionAuthentication

> Please provide us with the following information:
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### 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
>
For "SQL Server to Azure SQL Database" with Powershell, TargetSqlConnectionAuthentication currently only supports two types: The authentication type for connection, which can be either SqlAuthentication or WindowsAuthentication.

Can it be extended to support "Active Directory Password" or managed identity?

### Any log messages given by the failure
>

### Expected/desired behavior
> "Active Directory Password" or managed identity authentication methods are supported.

### OS and Version?
> Windows 7, 8 or 10. Linux (which distribution). macOS (Yosemite? El Capitan? Sierra?)

### Versions
>

### Mention any other details that might be useful

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> Thanks! We'll be in touch soon.

Comece localizando TargetSqlConnectionAuthentication e revisando como as opções existentes SqlAuthentication e WindowsAuthentication são tratadas. Esclareça se o objetivo é Active Directory Password, managed identity ou ambos; considera-se concluído quando o método de autenticação selecionado é aceito para migrações de SQL Server para Azure SQL Database e funciona pelo fluxo do PowerShell.

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