bitswap: add the requesting peer ID to context

[burdiyan]

This commit adds the peer.ID of the requesting peer to the context, which can be used downstream in the blockstore or other components used by Bitswap.

This could be very useful for custom logging, or accessing the peer ID in custom block stores.

[hsanjuan]

Triage:

• We assume you have tested this and it works for you (the modified context ends up at the blockstore.Get() or blockstore.GetMany() layer) (we don't know if this is the case).
• To accept this, we would need a test in bitswap with a mocked blockstore that reads back the peer ID from the context. Otherwise it is very likely that this will somehow break in a future refactor without anyone noticing.

[lidel]

Triage notes:

• main blocker: this should be opt-in via config option when constructing bitswap instance
• needs tests
• FYSA we have something similar in https://github.com/burdiyan/boxo/blob/main/bitswap/client/traceability/block.go where we have ability to enable extra metadata (and its opt-in)