[PM-2383] Bulk collection assignment (#3919)

* [PM-2383] Add bulk add/remove collection cipher repository methods

* [PM-2383] Add additional authorization helpers for CiphersControlle

* [PM-2383] Add /bulk-collections endpoint to CiphersController.cs

* [PM-2383] Add EF implementation for new CollectionCipherRepository methods

* [PM-2383] Ensure V1 logic only applies when the flag is enabled for new bulk functionality

src/Api/Vault/Models/Request/CipherBulkUpdateCollectionsRequestModel.cs

@@ -0,0 +1,15 @@
+namespace Bit.Api.Vault.Models.Request;
+
+public class CipherBulkUpdateCollectionsRequestModel
+{
+    public Guid OrganizationId { get; set; }
+
+    public IEnumerable<Guid> CipherIds { get; set; }
+
+    public IEnumerable<Guid> CollectionIds { get; set; }
+
+    /// <summary>
+    /// If true, the collections will be removed from the ciphers. Otherwise, they will be added.
+    /// </summary>
+    public bool RemoveCollections { get; set; }
+}