[extension/azureauth] Add support to be used in receivers

[constanca-m]

Component(s)

extension/azureauth

Is your feature request related to a problem? Please describe.

For the extension to have support to be used in receivers, it needs to implement:

• Interface extensionauth.Server so that it can check if requests have valid authenticaton
• Interface azcore.TokenCredential so the receivers can get a token if necessary (it will be for all azure receivers).

Describe the solution you'd like

All the examples are in the New component issue: #38908.

Describe alternatives you've considered

No response

Additional context

No response

[github-actions]

Pinging code owners:

• extension/azureauth: @constanca-m

See Adding Labels via Comments if you do not have permissions to add labels yourself.