Update Azure Batch plugin to return stdout, stderr, and runtime exceptions

[araghukas]

See related issue: AgnostiqHQ/covalent-awsbatch-plugin#53

Currently, the Azure Batch plugin uses a BlobServiceClient to retrieve only the task result. The stdout/stderr output streams and any runtime exceptions are neglected.

There are two important reasons for fixing this:

1. The intended UX is incomplete without outputs, error messages, or exceptions being relayed back to the user.
2. The present QElectron DB implementation extracts the DB-relevant data from the output stream. If the task output is inaccessible, there will be no server-side QElectron DB and hence no QElectron UI functionality.