Artifically limit IOPS for blob storage with Azurite

### Which service(blob, file, queue, table) does this issue concern?
blob, also files?

### Feature Request - Configurable IOPS limits
In azure a storage account can be limited by IOPS (IO operations per second). Azurite does not appear to support configuring an IOPS limit.

Currently the only way of testing IOPS limitations (to my knowledge) is by using a real storage account & accruing the associated costs. Alot of the IOPS limits in azure blob storage are quite high, and difficult to hit in a pre-production environment.

Is this possible now with Azurite or can it be added in the future?