Moved vendored js/css into public/vendor and documented sources (#1484) (#2241)

* Cleaning up public/ and documenting js/css libs.

This commit mostly addresses #1484 by moving vendor'ed plugins into a
vendor/ directory and documenting their upstream source and license in
vendor/librejs.html.

This also proves gitea is using only open source js/css libraries which
helps toward reaching #1524.

* Removing unused css file.

The version of this file in use is located at:
  vendor/plugins/highlight/github.css

* Cleaned up librejs.html and added javascript header

A SafeJS function was added to templates/helper.go to allow keeping
comments inside of javascript.

A javascript comment was added in the header of templates/base/head.tmpl
to mark all non-inline source as free.

The librejs.html file was updated to meet the current librejs spec. I
have now verified that the librejs plugin detects most of the scripts
included in gitea and suspect the non-free detections are the result of
a bug in the plugin. I believe this commit is enough to meet the C0.0
requirement of #1534.

* Updating SafeJS function per lint suggestion

* Added VERSIONS file, per request

public/vendor/plugins/codemirror/mode/eiffel/eiffel.js

@@ -0,0 +1,160 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+(function(mod) {
+  if (typeof exports == "object" && typeof module == "object") // CommonJS
+    mod(require("../../lib/codemirror"));
+  else if (typeof define == "function" && define.amd) // AMD
+    define(["../../lib/codemirror"], mod);
+  else // Plain browser env
+    mod(CodeMirror);
+})(function(CodeMirror) {
+"use strict";
+
+CodeMirror.defineMode("eiffel", function() {
+  function wordObj(words) {
+    var o = {};
+    for (var i = 0, e = words.length; i < e; ++i) o[words[i]] = true;
+    return o;
+  }
+  var keywords = wordObj([
+    'note',
+    'across',
+    'when',
+    'variant',
+    'until',
+    'unique',
+    'undefine',
+    'then',
+    'strip',
+    'select',
+    'retry',
+    'rescue',
+    'require',
+    'rename',
+    'reference',
+    'redefine',
+    'prefix',
+    'once',
+    'old',
+    'obsolete',
+    'loop',
+    'local',
+    'like',
+    'is',
+    'inspect',
+    'infix',
+    'include',
+    'if',
+    'frozen',
+    'from',
+    'external',
+    'export',
+    'ensure',
+    'end',
+    'elseif',
+    'else',
+    'do',
+    'creation',
+    'create',
+    'check',
+    'alias',
+    'agent',
+    'separate',
+    'invariant',
+    'inherit',
+    'indexing',
+    'feature',
+    'expanded',
+    'deferred',
+    'class',
+    'Void',
+    'True',
+    'Result',
+    'Precursor',
+    'False',
+    'Current',
+    'create',
+    'attached',
+    'detachable',
+    'as',
+    'and',
+    'implies',
+    'not',
+    'or'
+  ]);
+  var operators = wordObj([":=", "and then","and", "or","<<",">>"]);
+
+  function chain(newtok, stream, state) {
+    state.tokenize.push(newtok);
+    return newtok(stream, state);
+  }
+
+  function tokenBase(stream, state) {
+    if (stream.eatSpace()) return null;
+    var ch = stream.next();
+    if (ch == '"'||ch == "'") {
+      return chain(readQuoted(ch, "string"), stream, state);
+    } else if (ch == "-"&&stream.eat("-")) {
+      stream.skipToEnd();
+      return "comment";
+    } else if (ch == ":"&&stream.eat("=")) {
+      return "operator";
+    } else if (/[0-9]/.test(ch)) {
+      stream.eatWhile(/[xXbBCc0-9\.]/);
+      stream.eat(/[\?\!]/);
+      return "ident";
+    } else if (/[a-zA-Z_0-9]/.test(ch)) {
+      stream.eatWhile(/[a-zA-Z_0-9]/);
+      stream.eat(/[\?\!]/);
+      return "ident";
+    } else if (/[=+\-\/*^%<>~]/.test(ch)) {
+      stream.eatWhile(/[=+\-\/*^%<>~]/);
+      return "operator";
+    } else {
+      return null;
+    }
+  }
+
+  function readQuoted(quote, style,  unescaped) {
+    return function(stream, state) {
+      var escaped = false, ch;
+      while ((ch = stream.next()) != null) {
+        if (ch == quote && (unescaped || !escaped)) {
+          state.tokenize.pop();
+          break;
+        }
+        escaped = !escaped && ch == "%";
+      }
+      return style;
+    };
+  }
+
+  return {
+    startState: function() {
+      return {tokenize: [tokenBase]};
+    },
+
+    token: function(stream, state) {
+      var style = state.tokenize[state.tokenize.length-1](stream, state);
+      if (style == "ident") {
+        var word = stream.current();
+        style = keywords.propertyIsEnumerable(stream.current()) ? "keyword"
+          : operators.propertyIsEnumerable(stream.current()) ? "operator"
+          : /^[A-Z][A-Z_0-9]*$/g.test(word) ? "tag"
+          : /^0[bB][0-1]+$/g.test(word) ? "number"
+          : /^0[cC][0-7]+$/g.test(word) ? "number"
+          : /^0[xX][a-fA-F0-9]+$/g.test(word) ? "number"
+          : /^([0-9]+\.[0-9]*)|([0-9]*\.[0-9]+)$/g.test(word) ? "number"
+          : /^[0-9]+$/g.test(word) ? "number"
+          : "variable";
+      }
+      return style;
+    },
+    lineComment: "--"
+  };
+});
+
+CodeMirror.defineMIME("text/x-eiffel", "eiffel");
+
+});