Extend the HTMXSelect widget to support other HTTP methods

[jeremystretch]

Proposed Changes

The HTMXSelect widget is used to dynamically re-render a form based on the selection of a field (e.g. when changing the type of a remote data source). Currently it supports only GET requests to accomplish this. This proposal would add support for all HTTP methods supported by HTMX: GET, POST, DELETE, PUT, and PATCH.

Justification

POST support is required to use HTMXSelect in a bulk edit form, as bulk edit views must always be accessed via a POST request to capture the selected object IDs. Support for the remaining methods should be added in the interest of completeness.