Remove SearchObserver, aim is to remove all observers

rails-observers gem is mostly unmaintained and is a pain to carry forward
new implementation contains significantly less magic as a bonus

spec/services/search_indexer_spec.rb

@@ -0,0 +1,30 @@
+require 'rails_helper'
+
+describe SearchIndexer do
+
+  it 'correctly indexes chinese' do
+    SiteSetting.default_locale = 'zh_CN'
+    data = "你好世界"
+    expect(data.split(" ").length).to eq(1)
+
+    SearchIndexer.update_posts_index(99, "你好世界", "", nil)
+
+    raw_data = PostSearchData.where(post_id: 99).pluck(:raw_data)[0]
+    expect(raw_data.split(' ').length).to eq(2)
+  end
+
+  it 'correctly indexes a post' do
+    data = "<a>This</a> is a test"
+
+    SearchIndexer.update_posts_index(99, data, "", nil)
+
+    raw_data, locale = PostSearchData.where(post_id: 99).pluck(:raw_data, :locale)[0]
+    expect(raw_data).to eq("This is a test")
+    expect(locale).to eq("en")
+
+    SearchIndexer.update_posts_index(99, "tester", "", nil)
+
+    raw_data = PostSearchData.where(post_id: 99).pluck(:raw_data)[0]
+    expect(raw_data).to eq("tester")
+  end
+end