Move CAVEStereoModule to TundraAddons repo

[jonnenauha]

Unmaintained for years now. Pretty much crashes right away when when you interact with the provided UI. This could even be default commented out in the TundraAddons repo cmake.

• Move the source dir
• Remove from all core .xml configs: plugins.xml and viewer.xml and moved to the addons.xml in the addon repo.
• Remove mentions from core MenuBar.js https://github.com/realXtend/naali/blob/tundra2/bin/jsmodules/startup/MenuBar.js#L70-L84 (Possibly we could make MenuBarAddons.js in the addons repo that gets copied to /bin/jsmodules/startup and added as js plugin to addons.xml.

[cadaver]

I couldn't reproduce crashes with a little testing (though did get a hang on exit after opening 2 windows), but yes, it is better to move this to addons if no-one will actively develop/maintain this.

[cadaver]

The Stereoscopy part is more solid than the CAVE part. You were right, using CAVE controls crashes Tundra immediately.