Issue #3608039 by davidsonjames: Add support for the Umami recorder script (session replay/heatmaps)

Issue #3608039 by davidsonjames: Implements the recorder support described in this issue: adds recorder_enabled/recorder_src config, a "Recorder" section on the settings form, and a second script tag in hook_page_attachments(). Tested locally against a live Umami instance emitting both the tracking script and recorder script.

Closes #3608039