Update Contexts to Olivero / remove bartik blocks.

[rosiel]

What does this Pull Request do?

Updates the contexts that place blocks (openseadragon - paged content and Collection) to place them in the olivero theme.

Related GitHub Issue:

• [BUG] Contexts don't place blocks properly - Starter Site assumes theme is Bartik, but we have Olivero #10

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

What's new?

• Openseadragon-paged content and collection now place their views in content_below in olivero.

• Removed all the bartik blocks that aren't used anymore (as far as i can tell)

• does NOT place the facet blocks (which are currently placed in Olivero) - that's a separate issue:

  • [FEATURE] Search view for site and search views for collections. #23

• 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? no

How should this be tested?

Load it up (e.g. edit your Makefile in ISLE, then spin up a fresh starter_dev)
Make a collection and a child - does the view show?
Make a book and some pages - does the openseadragon viewer show?

Documentation Status

• Does this change existing behaviour that's currently documented? no
• Does this change require new pages or sections of documentation? no
• Who does this need to be documented for? n/a
• Associated documentation pull request(s): ___ or documentation issue ___

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/committers

[rosiel]

Closing; superseded by #39