Metadata for `add` and `import`

[rvagg]

Extend ImportOptions and AddOptions to include metadata?: Record<string, string> and extend the CLI to allow provision of this. I suggest --metadata key=value where you can provide as many --metadata arguments as you want (until the contract rejects it for putting too many). value can be an empty string.

This then needs to be plumbed through UploadFlowOptions passed to performUpload() which can then be passed in to executeUpload() which already accepts an optional metadata (we just don't currently use it there).

In addition, some CLI special case sugar we are considering for EIP 8004 to get consistent and well-formed metatadata (spit-balling here, feel free to propose better alternatives to getting this metadata in):

• --8004-type=<registration|validationrequest|validationresponse|feedback>
• --8004-agent=id

You would have to provide both, or neither.

They would map internally to --metadata 8004registration=agentId or --metadata 8004validationrequest=agentId, etc.

[rvagg]

Additional requirement: we need data set metadata too. This should be passed down in to initializeSynapse()'s config object. I think --data-set-metadata using the same format would be OK for this (with a hidden alias that allows --dataset-metadata since this has come up before as an annoyance).

When they have the --8004.. flags, then we also internally map that to --data-set-metadata erc8004Files= (i.e. just the key, empty value).