DP+ configuration Configuration Form - with ability to customize select settings on a resource-by-resource basis

[jqnatividad]

Currently, there are universal DP+ settings that apply to all resources.

https://github.com/dathere/datapusher-plus/blob/main/ckanext/datapusher_plus/config.py

Now that DP+ is an extension, it'd be nice if we can have a configuration form to customize select DP+ settings on a resource-per-resource basis.

The DP+ configuration form will be available to the Dataset Editor/Sysadmin only.

For Dataset Editors, only select settings will be configurable.

Sysadmins will have the ability to customize all settings EXCEPT system level settings that should be changed by manually by editing the ckan.ini (e.g. datastore_urls, path of qsv binary, etc.).

[jqnatividad]

Consolidating #60 ("Per resource Datapusher+ job configuration", 2023) into this issue — it described the same per-resource DP+ config feature, less specifically. Closed as a duplicate of this one.

Carrying forward the one concrete design detail from #60 so it isn't lost when that thread closes:

#60 proposed a specific storage + UI mechanism for per-resource config:

1. Storage — a resource extra field named dpplus_job_config holding a DP+ job-configuration JSON blob. When present and valid, DP+ applies that config for just that job (selectively enabling/disabling geocoding, PII screening, auto-spatial-extent, summary stats, etc.).
2. UI — a standard DP+ scheming widget so CKAN installs can drop a job-configurator into their resource schema quickly, rather than each install hand-rolling one.

That extra-field-as-storage + reusable-scheming-widget approach is a reasonable implementation path for this issue's configuration form, and pairs naturally with the role-based access model described above (the widget renders the curated subset for Dataset Editors, the full set for Sysadmins). Worth weighing when this gets picked up.