Tracking: Improve API based on user feedback

[matheus23]

In the #iroh-blobs channel on discord users keep getting confused about how to do basic things like fetching metadata, using the push API, etc.

I'd say the iroh-blobs API still needs lots of work to get less confusing. This issue is an attempt to collect user feedback so that we know what trips users up. I'll try to add things to this list when they come up.

• There doesn't seem to be a way of exporing a whole collection in one go: https://discord.com/channels/1161119546170687619/1175172809354387476/1438967481757860011
• Creating & transferring a collection from a path is much harder than doing this with a blob: https://discord.com/channels/1161119546170687619/1175172809354387476/1461045085822259250
• The execute_push API seems to be hard to find: https://discord.com/channels/1161119546170687619/1175172809354387476/1485557251258322984
• There are some useful APIs that only exist as low-level APIs (e.g. get_hash_seq_and_sizes): https://discord.com/channels/1161119546170687619/1175172809354387476/1486633591403450398