Replace "Azure Active Directory" with "Microsoft Entra ID" to reflect the renaming of that product

[nblumhardt]

E.g. in setting names and in the System > Authentication Provider screen:

The API will accept the previous names of settings such as AzureADClientKey when requests are marked with an appropriate media type; otherwise, new setting names such as EntraIDClientKey are expected.

When setting the AuthenticationProvider value for a Seq instance, "Microsoft Entra ID" is now expected where previously "Azure Active Directory" would have been used.

See the Seq.Api project's SettingName enumeration for all currently-accepted setting names.