Cardano Updates

And swap the argument order of readHashes and read. It's only elem that
follows the x `elem` set' convention.

In preparatioon for adding a new blocked bloom filter implementation,
make various adjustments to the existing API so that it will be easier
for the new implementation to match it.

We provide a low level API for bloom filter inserts and elem operations.
These allow for sharing a single hash calculation across many filters,
and potentially allows for prefetching.

Now instead of a CheapHashes type and operations in the Hash module,
each of the two implementations (Classic and Blocked) provide a Hashes
type and constructor. The classic one uses the (renamed) CheapHashes,
while the Blocked one uses its own scheme.

Add a few missing `not-home` haddock options to modules

This adds a dependency on the `utf8-string` package, but its dependency
footprint is very small so it does not seem much of an issue to have an extra
dependency just for this.

Mostly so that `lsm-tree` comes with a few batteries included

It's now close to the `FencePointerIndexType` type, which is where the Minimal
size law is defined

It's part of the definition of the Ordering-preserving law for the
`SerialiseKey` class, and it is also mentioned in the documentation.

The Order-preserving law now applies to this class instead of `SerialiseKey`.
Other than that, the class is empty.