Further Azure Storage API support

- [ ] 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

