Claim zaps in batches

[benthecarman]

Helps with #1163

Before we'd claim each zap individually and this could cause problems because relays would send the events with the newest first, so if we stopped claiming the zaps for whatever reason (user closes app), then we'd miss the remaining zaps because we'd set our sync timestamp to the first one we claimed. This fixes this problem by instead accumulating all the zaps until we get the End Of Stored Events message from the relays, and then claiming the zaps, this way we know we got everything from the relay.

[TonyGiorgio]

When does the dm sync timestamp saved?

[benthecarman]

After an individual ecash notification is handled:

mutiny-node/mutiny-core/src/hermes.rs

Line 764 in ed3731a

storage.set_dm_sync_time(created_at.as_u64(), true)?;

[TonyGiorgio]

After an individual ecash notification is handled:

I don't know what that means. When in the lifetime of an ecash redemption does this even take place?

I guess instead of asking, I should specify that if we're going to move the redemption of the ecash to a batcahable thing in the end, then the timestamp should only be saved once the batched ecash completes fully.

[benthecarman]

I see what you're saying, moved it to set the timestamp after the batch, that should be safer