Further Azure Storage API support

[joeapearson]

• Blob metadata
• Blob Tags
• Find blobs by tags
• Lease blob
• Copy / abort copy blob
• Copy blob from URL
• Undelete blonb
• Set blob tier
• Blob batch

Goal is to create something that:

1. Provides similar or better functionality to that of an officially provided client in another language
2. Feels natural to use in Elixir