Revert brand-related preset changes

I'm not convinced we shouldn't be encouraging simply tagging
`name=McDonald's`, `name=Shell`, etc., without `brand` or
`operator` at all.

data/presets/fields/brand_fast_food.json

@@ -1,6 +0,0 @@
-{
-    "key": "brand",
-    "type": "text",
-    "placeholder": "McDonald's, Subway, KFC...",
-    "label": "Brand"
-}

data/presets/fields/brand_fuel.json

@@ -1,6 +0,0 @@
-{
-    "key": "brand",
-    "type": "text",
-    "placeholder": "Shell, Exxon, BP...",
-    "label": "Brand"
-}

data/presets/fields/brand_restaurant.json

@@ -1,6 +0,0 @@
-{
-    "key": "brand",
-    "type": "text",
-    "placeholder": "Olive Garden, Applebee's, TGI Friday's...",
-    "label": "Brand"
-}