Add integration test for blob creation

[brunocalza]

Test cases

• Create a blob and download it
• Create a blob with custom metadata and check the metadata
• Upload a large blob (5 GiB) and download it
• Upload a blob and list it
• Upload a bunch of blobs (10) and list them
• Upload a bunch of blobs and use limit and offset to paginate

This addresses points 2, 3, 5 https://www.notion.so/Mainnet-Protocol-Readiness-1badfc9427de8073b074e5889058b640?pvs=4#1badfc9427de80eba174e7681a778292