add task that can Restore Asset/Component metadata to component database from Blob Store contents

Background

In a number of situations, users will need to repair their component metadata from the disaster recovery information stored in the blob store properties.

• component metadata in database is a complete write-off (unrecoverally corrupt OrientDB, no usable backup)
• component metadata is functional, was restored from an earlier point than the blob stores - so there are blobs with no component metadata

Acceptance

• Admins can repair/rebuild component database metadata from blobs
• Component metadata (sufficient to use the format) is created
• This process can be run on a subset of repositories, and/or blob stores
• target Maven2 format repositories initially, extendable to other formats in the future