Pick default wheel dist dir based on build backend

[analog-cbarber]

Most build systems seem to put wheels in the dist/ subdir of the project, but there are some exceptions:

• hatchling lets you override the dest dir using the tool.match.build.directory option
• pdm-backend defaults to the .pdm-build subdir. This can be overridden but not from pyproject option: https://pdm-backend.fming.dev/hooks/#change-the-build-directory

The hatchling backend uses the dist/ dir whether run from hatch build or pip wheel, but for poetry and flit-core, pip wheel just writes into the current directory.

Are there other build backends to consider?

We should use dist/ by default, but

• use tool.hatch.build.directory if using hatchling backend
• use .pdm-build/ if using pdm-backend and try to figure out how to check the pdm hook

Since dist/ is pretty much the standard, it isn't so bad if we just stick with that and let users override it using option specific to this tool.