Deprecate islandora_defaults (Note: do not action till islandora-starter-site is ready) future ticket

[lutaylor]

Overview

NOTE: Future ticket not to be done till islandora-starter-site and acceptance criteria is good.

As per the Islandora modularization project islandora_defaults will be deprecated in favor of a starter site see issue: Islandora-Devops/islandora-starter-site#2

The intent is to simplify expectations and maintenance. This is to help facilitate the communities end goal to modularize Islandora into largely independent Drupal modules that let Drupal sites pick and choose their repository features.

It is recommended that a code freeze is implemented while this work is ongoing.

Acceptance Criteria
-islandora_defaults has been deprecated repository has been updated to reflect this.
-Islandora-Devops/islandora-starter-site#2 is resolved and islandora-starter-site is released ISLE/playbook have been updated to use new starter site

Reference
https://docs.google.com/document/d/1fx8PvSpft8c3OPMLrN5SjaqOhcHOuRr_xjgqnBe8gg4/edit#heading=h.w3w654y9wz7s

Contacts
On Islandora slack
Rosie Le Faive (Product owner)
Luke Taylor (Project Manager)