Roll out Bus pause and resume to all IAP operations, across all applications

[dallmair]

In sblib 2.10, we implemented cooperative pause+resume, focused on the bootloader usage scenario as our BL does the most IAP, by far. Now that both pause and resume are reliable, we can and should roll this feature out to all applications and all IAP operations.

Today, there are a bunch of code paths that end up in IAP, and it's not clear whether it's sufficient to have IAP call into Bus to pause bus access as that might (!) cause deadlocks or timeouts. We need to analyze the call patterns and see, what the best approach to this is.