Don't enable bartik.

[rosiel]

GitHub Issue: addresses part of #248

• Other Relevant Links (Google Groups discussion, related pull requests,
  Release pull requests, etc.)

What does this Pull Request do?

Doesn't enable bartik, since defaults is no longer being installed. When it gets installed, there are a number of Bartik blocks added to the starter site's config suite, which is bad.

What's new?

• Don't enable bartik.
• Does this change require documentation to be updated? No.
• Does this change add any new dependencies? No.
• Does this change require any other modifications to be made to the repository
  (i.e. Regeneration activity, etc.)? No.
• Could this change impact execution of existing code? If you are requiring bartik to be enabled, make sure you do it somewhere.

How should this be tested?

Before:

• load the starter site. Load a config or two in the UI.
• Export configs. Note that a lot of blocks were added to the configs.
  After:
• load the starter site. Load some configs in the UI.
• Export configs. No bartik blocks should be added to the configs.

Additional Notes:

Any additional information that you think would be helpful when reviewing this
PR.

Interested parties

Tag (@ mention) interested parties or, if unsure, @Islandora-Devops/committers

[seth-shaw-asu]

Works for me. 🔥 bartik.