Revert indexers work from #461

[mjgiarlo]

Why was this change made?

Because it breaks production and people have work to do.

Re-opens #457 which will be discussed on Tuesday.

How was this change tested?

CI. This has been confirmed to work in both stage and prod, tested by @amyehodge and @aaron-collier and myself.

Which documentation and/or configurations were updated?

None

[mjgiarlo]

NOTE: We determined that a possibley related error w/ the homepage not rendering was being caused in the stage environment due to bad data in solr (root cause unknown but possibly related to either recent indexing changes or integration tests not doing the right thing). If we see this error again in any environment, drop into a console and execute the following commands (from the Hydrus collection class) to determine which collections are affected:

user = User.find_by(email: 'mjgiarlo@stanford.edu') # make sure to specify user that is seeing the bug
apo_pids = Hydrus::Collection.apos_involving_user(user) # get user's APOs
coll_pids = Hydrus::Collection.collections_of_apos(apo_pids) # get user's collections
initial_item_counts = Hash[Hydrus::GenericObject.status_labels(:item).keys.map { |s| [s, 0] }] # get item counts
counts = Hash[coll_pids.map { |cp| [cp, initial_item_counts] }] # get item counts from collections
h = Hydrus::Collection.squery_item_counts_of_collections(counts.keys) # generate Solr query given counts from collections
resp, sdocs = Hydrus::Collection.issue_solr_query(h) # issue the Solr query and store results
collection_druids = Hydrus::Collection.get_facet_counts_from_response(resp).map { |fc| fc['value'] if fc['pivot'].nil? }.compact.map { |fedora_uri| fedora_
uri.delete_prefix('info:fedora/') } # iterate over collection facet counts and return druids of collections that would cause homepage to raise exception
collection_druids.each do |collection_druid|
  Hydrus::Collection.find(collection_druid).items.each do |child_item|
    ActiveFedora.solr.conn.add(child_item.to_solr, add_attributes: { commitWithin: 1000 })
  end
  ActiveFedora.solr.conn.add(Hydrus::Collection.find(collection_druid).to_solr, add_attributes: { commitWithin: 1000 })
end