Make idempotency token, tags always available in the create form

[JasonWeill]

Problem

Currently, the idempotency token and tags are shown in the "additional options" sections of the create job form using the "advanced options" extension point. This requires extension point developers to copy our open source code if they wish to modify the "additional options" while keeping the idempotency token and tags as they are.

Proposed Solution

Always make the idempotency token and tags visible in the "additional options" section; make the open source extension point's contents blank, so that extension writers can add to, but not delete idempotency token or tags from, this section.