[Feature] Add support for upper and lover case variables (like myPet -> mypet and MYPET)

[anivit00]

It would be very helpful to have the possibility to use the upper and lover case variables in the templates.

In my case I want to define a camel case variable myModueName and use in the templates also MYMODULENAME (e.g. as prefix for C defines) as also mymoduleame (e.g. as prefix for the static function/variable names etc.). As the extension has already a great number of complex cases supported this request might be a really a easy one from the implementation point of view but very helpful for a lot of uses cases.