[TYPO3-ect] Provide general AJAX call handler for backend functions/modules with mID technique

[Franz Holzinger]

Hello Elmar,

> I don't like the names eID or mID either. They don't tell me what it is.
> I can't remember wich charaters have which case. There is no stringent
> system behind the T3 namings. It's that kind of cryptic stuff, again. 
> 
Any short naming is fine with me and no problem at all.

> Maybe aband the eID interface and overwork the concept as a whole.
> 
I am still using the xajax extension at the moment. Can some
improvements made inside of it? Or we could develop a new extension
which could be used by any specific AJAX extension.

Xajax has a
var xajaxRequestUri = ...;

However I want to juse AJAX with and without eID.

One time a full extension listing should be shown, so everything has to
be loaded to make the extension full workable.

The second time only a very short and fast database call should be done.
Therefore I need eID with this function.

So we need an interface to all functions registered with
xajax->registerFunction, to tell the AJAX, that is shall use eID with
xajaxRequestUri or not.

- Franz