feat: import from a remote source

[alvin-reyes]

Changes

• introduce transfer_parameters to allow import deals to pull from a remote source when making a deal
• introduce batch imports to asynchronously batch import deal calls.

Transfer Parameters

This allows users to specify a remote source for import deals.

• This PR introduces a new metadata field called transfer_parameters that's only valid/allowed for import type deals
• This new field will enable the deal-maker to specify a URL source of file.

Sample below:

When the transfer_parameters is specified, delta will use the URL as the source of the import.

    "cid": "bafybeicgdjdvwes3e5aaicqljrlv6hpdfsducknrjvsq66d4gsvepolk6y",
    "miner": "f01963614",
    "piece_commitment": {
        "piece_cid": "baga6ea4seaqdgtooshkmlmbu4hesd5asp7g3p4yd7s4tjmrbkx676ba5mlu2kcy",
        "padded_piece_size": 2097152
    },
    "transfer_parameters": {
        "url":"https://ipfs.io/ipfs/bafybeicgdjdvwes3e5aaicqljrlv6hpdfsducknrjvsq66d4gsvepolk6y"
    },
    "connection_mode": "import",
    "size": 1157859,
    "remove_unsealed_copy": false,
    "skip_ipni_announce": true,
    "duration_in_days": 521,
    "start_epoch_in_days": 7
}

Batch Imports

Introduced the following new endpoints

• /deal/batch/imports - this takes an array of import deal metadata and creates a batch job that runs async. The user gets a batch id that can be used to check the status of the job and it's associated content.
• /open/stats/batch/imports/:batchId - this is to check the status of the batch and the contents associated to it.