[Pm 3797 Part 2] Add emergency access rotations (#3434)

## Type of change

<!-- (mark with an `X`) -->

```
- [ ] Bug fix
- [ ] New feature development
- [x] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other
```

## Objective
<!--Describe what the purpose of this PR is. For example: what bug you're fixing or what new feature you're adding-->
See #3425 for part 1 and background.

This PR adds emergency access to the rotation. All new code is hidden behind a feature flag.

The Accounts controller has also been moved to Auth ownership.

## Code changes
<!--Explain the changes you've made to each file or major component. This should help the reviewer understand your changes-->
<!--Also refer to any related changes or PRs in other repositories-->

* **file.ext:** Description of what was changed and why
* **AccountsController.cs:** Moved to Auth ownership. Emergency access validation was added (as well as initializing empty lists to avoid errors).
* **EmergencyAccessRotationValidator.cs:** Performs validation on the provided list of new emergency access keys.
* **EmergencyAccessRepository.cs:** Adds a method to rotate encryption keys. This is added to a list in the `RotateUserKeyCommand` that the `UserRepository` calls so it doesn't have to know about all the domains.

## Before you submit

- Please check for formatting errors (`dotnet format --verify-no-changes`) (required)
- If making database changes - make sure you also update Entity Framework queries and/or migrations
- Please add **unit tests** where it makes sense to do so (encouraged but not required)
- If this change requires a **documentation update** - notify the documentation team
- If this change has particular **deployment requirements** - notify the DevOps team

src/Api/Startup.cs

@@ -7,6 +7,9 @@ using Stripe;
 using Bit.Core.Utilities;
 using IdentityModel;
 using System.Globalization;
+using Bit.Api.Auth.Models.Request;
+using Bit.Api.Auth.Validators;
+using Bit.Core.Auth.Entities;
 using Bit.Core.IdentityServer;
 using Bit.SharedWeb.Health;
 using Microsoft.IdentityModel.Logging;
@@ -135,6 +138,9 @@ public class Startup
 
         // Key Rotation
         services.AddScoped<IRotateUserKeyCommand, RotateUserKeyCommand>();
+        services
+            .AddScoped<IRotationValidator<IEnumerable<EmergencyAccessWithIdRequestModel>, IEnumerable<EmergencyAccess>>,
+                EmergencyAccessRotationValidator>();
 
         // Services
         services.AddBaseServices(globalSettings);