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/stex/test.js

@@ -0,0 +1,123 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+(function() {
+  var mode = CodeMirror.getMode({tabSize: 4}, "stex");
+  function MT(name) { test.mode(name, mode, Array.prototype.slice.call(arguments, 1)); }
+
+  MT("word",
+     "foo");
+
+  MT("twoWords",
+     "foo bar");
+
+  MT("beginEndDocument",
+     "[tag \\begin][bracket {][atom document][bracket }]",
+     "[tag \\end][bracket {][atom document][bracket }]");
+
+  MT("beginEndEquation",
+     "[tag \\begin][bracket {][atom equation][bracket }]",
+     "  E=mc^2",
+     "[tag \\end][bracket {][atom equation][bracket }]");
+
+  MT("beginModule",
+     "[tag \\begin][bracket {][atom module][bracket }[[]]]");
+
+  MT("beginModuleId",
+     "[tag \\begin][bracket {][atom module][bracket }[[]id=bbt-size[bracket ]]]");
+
+  MT("importModule",
+     "[tag \\importmodule][bracket [[][string b-b-t][bracket ]]{][builtin b-b-t][bracket }]");
+
+  MT("importModulePath",
+     "[tag \\importmodule][bracket [[][tag \\KWARCslides][bracket {][string dmath/en/cardinality][bracket }]]{][builtin card][bracket }]");
+
+  MT("psForPDF",
+     "[tag \\PSforPDF][bracket [[][atom 1][bracket ]]{]#1[bracket }]");
+
+  MT("comment",
+     "[comment % foo]");
+
+  MT("tagComment",
+     "[tag \\item][comment % bar]");
+
+  MT("commentTag",
+     " [comment % \\item]");
+
+  MT("commentLineBreak",
+     "[comment %]",
+     "foo");
+
+  MT("tagErrorCurly",
+     "[tag \\begin][error }][bracket {]");
+
+  MT("tagErrorSquare",
+     "[tag \\item][error ]]][bracket {]");
+
+  MT("commentCurly",
+     "[comment % }]");
+
+  MT("tagHash",
+     "the [tag \\#] key");
+
+  MT("tagNumber",
+     "a [tag \\$][atom 5] stetson");
+
+  MT("tagPercent",
+     "[atom 100][tag \\%] beef");
+
+  MT("tagAmpersand",
+     "L [tag \\&] N");
+
+  MT("tagUnderscore",
+     "foo[tag \\_]bar");
+
+  MT("tagBracketOpen",
+     "[tag \\emph][bracket {][tag \\{][bracket }]");
+
+  MT("tagBracketClose",
+     "[tag \\emph][bracket {][tag \\}][bracket }]");
+
+  MT("tagLetterNumber",
+     "section [tag \\S][atom 1]");
+
+  MT("textTagNumber",
+     "para [tag \\P][atom 2]");
+
+  MT("thinspace",
+     "x[tag \\,]y");
+
+  MT("thickspace",
+     "x[tag \\;]y");
+
+  MT("negativeThinspace",
+     "x[tag \\!]y");
+
+  MT("periodNotSentence",
+     "J.\\ L.\\ is");
+
+  MT("periodSentence",
+     "X[tag \\@]. The");
+
+  MT("italicCorrection",
+     "[bracket {][tag \\em] If[tag \\/][bracket }] I");
+
+  MT("tagBracket",
+     "[tag \\newcommand][bracket {][tag \\pop][bracket }]");
+
+  MT("inlineMathTagFollowedByNumber",
+     "[keyword $][tag \\pi][number 2][keyword $]");
+
+  MT("inlineMath",
+     "[keyword $][number 3][variable-2 x][tag ^][number 2.45]-[tag \\sqrt][bracket {][tag \\$\\alpha][bracket }] = [number 2][keyword $] other text");
+
+  MT("displayMath",
+     "More [keyword $$]\t[variable-2 S][tag ^][variable-2 n][tag \\sum] [variable-2 i][keyword $$] other text");
+
+  MT("mathWithComment",
+     "[keyword $][variable-2 x] [comment % $]",
+     "[variable-2 y][keyword $] other text");
+
+  MT("lineBreakArgument",
+    "[tag \\\\][bracket [[][atom 1cm][bracket ]]]");
+})();