Always set bundle + coerce query params

[stevelacey]

What does this PR do?

Makes the bundle always available via GET, currently only available on list apis, and adds coersion for true/false/null when the bundle is derived from the query string.

Note that this coercion is more strict than elsewhere given we can't assume that string isn't the correct type unless it's precisely these values.

We can't assume that 0/1 are bools, or that a numeric string should be an int, but we can reasonably assume that no one wants a string "true"/"false"/"null" when passing query params.

What issue does this solve?

The bundle provides a selection of conveniences over using the request QueryDicts directly, so needs to be available always, life also gets a lot easier when query string bools are bools.

This makes it easier for developers to patch in arbitrary API tweaks like swapping out a serializer when a query parameter like ?nextgen=true is passed.

Checklist

• This PR increases test coverage