Drop bower support by deleting bower.json

As part of removing traces of bower since it has been
deprecated for several years already.

Refs https://github.com/janl/mustache.js/pull/725

bower.json

@@ -1,20 +0,0 @@
-{
-  "name": "mustache.js",
-  "main": "mustache.js",
-  "homepage": "https://github.com/janl/mustache.js",
-  "authors": [
-    "mustache.js Authors <http://github.com/janl/mustache.js>"
-  ],
-  "description": "Logic-less {{mustache}} templates with JavaScript",
-  "keywords": ["mustache", "template", "templates", "ejs"],
-  "moduleType": [
-    "amd",
-    "globals",
-    "node"
-  ],
-  "license": "MIT",
-  "ignore": [
-    "**/.*",
-    "test"
-  ]
-}