[Azure Blob Storage] (binding / state) local emulator support

[alexdrenea]

Describe the feature

At this time, the Azure Blob Storage components (both binding and state) require just AccountName and Key.

The downstream go library (azblob) automatically appends "blob.core.windows.net" at the end of the given AccountName thus preventing us to use the local emulator (which runs at 127.0.0.1:10000)

The Azure Table components already support this by using an extra metadata option that allows specifying a custom endpoint.

@ItalyPaleAle

[berndverst]

We will keep this in mind when working on:

#1529 #1530

[berndverst]

I believe this should be working now.