Ability to restrict a user's ability to change passwords (#1018)

* Implemented a new role "Change Password". This role allows you to change your own password. By default, all users will have it. A user can have it removed arbitrarliy.

Removed components that are no longer going to be used.

* Cleaned up some code

API/Data/MigrateChangePasswordRoles.cs

@@ -0,0 +1,18 @@
+using System.Threading.Tasks;
+using API.Constants;
+using API.Entities;
+using Microsoft.AspNetCore.Identity;
+
+namespace API.Data;
+
+public static class MigrateChangePasswordRoles
+{
+    public static async Task Migrate(IUnitOfWork unitOfWork, UserManager<AppUser> userManager)
+    {
+        foreach (var user in await unitOfWork.UserRepository.GetAllUsers())
+        {
+            await userManager.RemoveFromRoleAsync(user, "ChangePassword");
+            await userManager.AddToRoleAsync(user, PolicyConstants.ChangePasswordRole);
+        }
+    }
+}