Deprecate / remove support for .vcg files in pyreverse

[DudeNr33]

Visual Compiler Graphs is currently one of the supported output formats for pyreverse.
However this is a very old format (the linked article talks about MS Windows 3.1 😀), and it is really hard to even find tools that can render this format.
The link included in the source code does not contain a download link as promised, and the mentioned debian package cannot be found anymore.

I talked to various colleagues that I thought might have heard about this format, but no one ever did.

Especially because verifying changes to the .vcg testdata is hard and might even scare potential contributors, I propose to deprecate - or even better, as it is seemingly very outdated and probably not used anymore - remove .vcg support entirely.

Maybe we could put the deprecation warning in 2.17 and remove it for 3.0?

[DanielNoord]

👍 remove!

[Pierre-Sassoulas]

In 3.0 even.

[DudeNr33]

Perfect!

I mean, we lose cool features like the fisheye view, but hey I guess that's the price to pay. 😆

[Pierre-Sassoulas]

The 90's were wild, impressive stuff.