v5.7.2

Nuthatch 5.7.2 moves init's output and a nest's identity into crates a browser tab can build, and
names the chain head when an address-history range ends above it. There is no storage migration, and
no nest's NID changes.

init and the nest identity as their own crates

The nest builder (RFC-0066) scaffolds and identifies a nest in a tab, so it needs init's own code
rather than a copy. The NID, the data identity and the manifest move into nuthatch-identity (#2097);
the contents of every file init writes, the semantic model and generate move into
nuthatch-scaffold (#2098), with the proxy, Sourcify and alias choices init makes from what it
fetched (#2100). Both crates are checked for wasm32 in CI. The network calls and the directory walk
stay in the binary.

The move changes no output. The NID and data identity of three fixed nests, taken before it, are
pinned in a test and unchanged, and init on USDC (a proxy), CryptoPunks and a two-contract local-ABI nest writes
directories byte-identical to 5.7.1's under diff -r.

An end above the head is named, not called a backfill

An Etherscan-style request ending at block 99,999,999, which means "everything", was refused by a
rotki-mode nest as "the 73,778,938 blocks above it are being backfilled". Those blocks do not exist
and nothing is backfilling them. The refusal now names the polled chain head and asks for a range
ending at or below it (#2106). Ranges ending below the head, which is all of rotki's own syncs, take
the path they took before.

Compatibility and upgrade

Replace the binary and restart. A 5.7.1 store is used as it is.