Feature Request: Dynamic check of available TR-064 actions and according parameters

[jhubig]

As requested in the frame of Pull Request #15 there would be a need for checking available actions and according location and uri parameters as defined in igddesc.xml and tr64desc.xml:

Reference: https://github.com/jhubig/FritzBoxShell/pull/15#issuecomment-736648507 by @chr-x

A wish for the future. FritzBoxShell should make use of the output of igddesc.xml and tr64desc.xml for setting uri= and location= and for verifying the existence of action=. I guess this wish is out of the scope of this pull request and if desired it should go to a new issue or pull request.