Note we're suppressing a UBSanitizer overflow error in UTs. That's
because our linter complains about a possible overflow, which never
happens, but tests are still failing because of it.
This is in order to prevent new incorrect uses of dht::shard_of() to
be accidentally added. Also, makes sure that all current uses are
caught by the compiler and require an explicit rename.
Contains methods to generate partition and clustering keys. In the case
of the former, one can specify the shard to generate keys for.
We currently have some methods to generate these but they are not
generic. Therefore the tests are littered by open-coded variants.
The methods introduced here are completely generic: they can generate
keys for any schema.
