Remove the data/shopify_liquid/(tags|filters|objects).yml files (#674)

### WHY are these changes introduced?

Fixes #656 

### WHAT is this pull request doing?

- Removes the usage of `data/shopify_liquid/tags.yml`, `data/shopify_liquid/filters.yml`, `data/shopify_liquid/objects.yml` in favor of the `SourceIndex`, which holds the most updated values for objects, filters, and tags.
- Transforms remaining `.yml` files to `.json` files, so that we only have 1 format.
- Adds some logic for existing objects, filters, tags, so that it resembles the existing `.yml` files content.

data/shopify_liquid/deprecated_filters.json

@@ -0,0 +1,22 @@
+{
+  "Liquid::ColorFilter": {
+    "hex_to_rgba": [
+      "color_to_rgb",
+      "color_modify"
+    ]
+  },
+  "Liquid::UrlFilter": {
+    "img_url": [
+      "image_url"
+    ],
+    "img_tag": [
+      "image_tag"
+    ],
+    "collection_img_url": [
+      "img_url"
+    ],
+    "product_img_url": [
+      "img_url"
+    ]
+  }
+}

data/shopify_liquid/plus_labels.json

@@ -0,0 +1,15 @@
+[
+  "alternative_payment_methods",
+  "breadcrumb",
+  "checkout_html_classes",
+  "checkout_scripts",
+  "checkout_stylesheets",
+  "content_for_footer",
+  "content_for_logo",
+  "content_for_order_summary",
+  "direction",
+  "locale",
+  "order_summary_toggle",
+  "skip_to_content_link",
+  "tracking_code"
+]