add some info tiddlers, that can be used by list and reveal widget

This plugin provides users with the possibilities, that otherwise just devs have.
With the plugin TiddlyWiki has the possibility to check information about "itself".

It implements several global macros. Those macros are just wrappers for the `$:/info/doc/location/xxxx` tiddlers. The global macros can be easily used by users to show info about the TW.

eg: 
 * `<<document-filename>>` was requested in the group. Mainly for documentation reasons in a teaching context.
 * `<<document-protocol>>` gives you the possibility to display different content if served from "file:  http:  https:" ...

The main info is done with `$:/info/doc/location/xxx` tiddlers. See documentation tiddlers in the plugin.

`$:/info/doc/location/filepath` is special, since depending on the path of the TW, it is extended to 

eg: If the filepath is: `languages/de-DE/` there will be the following shadow tiddlers:
 * `$:/info/doc/location/filepath/is/languages` and
 * `$:/info/doc/location/filepath/is/de-DE`

These tiddlers can be used with the reveal widget, to display special content, depending on the path. ... 

Might `contains` be clearer than `is`?