Previously init multipart upload stores metadata of an object which is
used for complete multipart. This patch makes azure gateway to store
metadata information of init multipart object in azure in the name of
'minio.sys.tmp/multipart/v1/<UPLOAD-ID>/meta.json' and uses this
information on complete multipart.
Previously minio gateway returns invalid bucket name error for invalid
meta data. This is fixed by returning BadRequest with 'Unsupported
metadata' in response.
Fixes#4891
Previously if any multipart part size > 100MiB is uploaded, azure
gateway returns error.
This patch fixes the issue by creating sub parts sizing each 100MiB of
given multipart part. On complete multipart, it fetches all uploaded
azure block ids for each parts and performs completion.
Fixes#4868
Aditya Manthramurthy