Prepare for send direct upload (#1174)

* Add sendId to path

Event Grid returns the blob path, which will be used to grab a Send and verify file size

* Re-validate access upon file download

Increment access count only when file is downloaded. File
name and size are leaked, but this is a good first step toward
solving the access-download race

src/Core/Services/ISendService.cs

@@ -13,5 +13,6 @@ namespace Bit.Core.Services
         Task CreateSendAsync(Send send, SendFileData data, Stream stream, long requestLength);
         Task<(Send, bool, bool)> AccessAsync(Guid sendId, string password);
         string HashPassword(string password);
+        Task<(string, bool, bool)> GetSendFileDownloadUrlAsync(Send send, string fileId, string password);
     }
 }