[PM-8220] New Device Verification (#5084)

* feat(BaseRequestValidator): 
Add global setting for new device verification.
Refactor BaseRequestValidator enabling better self-documenting code and better single responsibility principle for validators.
Updated DeviceValidator to handle new device verification, behind a feature flag.
Moved IDeviceValidator interface to separate file.
Updated CustomRequestValidator to act as the conduit by which *Validators communicate authentication context between themselves and the RequestValidators.
Adding new test for DeviceValidator class.
Updated tests for BaseRequestValidator as some functionality was moved to the DeviceValidator class.

src/Identity/IdentityServer/CustomValidatorRequestContext.cs

@@ -1,11 +1,43 @@
 using Bit.Core.Auth.Models.Business;
 using Bit.Core.Entities;
+using Duende.IdentityServer.Validation;
 
 namespace Bit.Identity.IdentityServer;
 
 public class CustomValidatorRequestContext
 {
     public User User { get; set; }
+    /// <summary>
+    /// This is the device that the user is using to authenticate. It can be either known or unknown.
+    /// We set it here since the ResourceOwnerPasswordValidator needs the device to know if CAPTCHA is required.
+    /// The option to set it here saves a trip to the database.
+    /// </summary>
+    public Device Device { get; set; }
+    /// <summary>
+    /// Communicates whether or not the device in the request is known to the user.
+    /// KnownDevice is set in the child classes of the BaseRequestValidator using the DeviceValidator.KnownDeviceAsync method.
+    /// Except in the CustomTokenRequestValidator, where it is hardcoded to true.
+    /// </summary>
     public bool KnownDevice { get; set; }
+    /// <summary>
+    /// This communicates whether or not two factor is required for the user to authenticate.
+    /// </summary>
+    public bool TwoFactorRequired { get; set; } = false;
+    /// <summary>
+    /// This communicates whether or not SSO is required for the user to authenticate.
+    /// </summary>
+    public bool SsoRequired { get; set; } = false;
+    /// <summary>
+    /// We use the parent class for both GrantValidationResult and TokenRequestValidationResult here for
+    /// flexibility when building an error response.
+    /// This will be null if the authentication request is successful.
+    /// </summary>
+    public ValidationResult ValidationErrorResult { get; set; }
+    /// <summary>
+    /// This dictionary should contain relevant information for the clients to act on.
+    /// This will contain the information used to guide a user to successful authentication, such as TwoFactorProviders.
+    /// This will be null if the authentication request is successful.
+    /// </summary>
+    public Dictionary<string, object> CustomResponse { get; set; }
     public CaptchaResponse CaptchaResponse { get; set; }
 }