testing/cagebreak: upgrade to 2.0.0

Release 2.0.0

This is a major release and includes BREAKING changes!

Breaking Changes:

• More intuitive switch of focus, next, prev and exchange (#20, 40 in Bugs.md) Cagebreak will probably still feel broadly the same though.
• Remove -r flag - This is replaced by output configuration.
• Socket disabled by default - The socket is enabled by invoking Cagebreak with the -e flag.
• Socket permissions restricted to the user of the Cagebreak process (700) This may require modification of scripts interacting with the socket with different UIDs than the UID of the Cagebreak process.
• Rename "Current frame" indicator to "Current tile"

Changelog:

• Move to wlr_scene
• Add events displaying change over the socket
  • this enables scripting tools
• Add support for scaling outputs (thanks to Oliver Friedmann)
• Remove -r flag
• Add rotation to output configuration
• Add cursor enable|disable flag
• Add input keyboard configuration
• Custom path flag for configuration file
• Restrict socket permissions to the user running cagebreak (700)
• Fix Issue 31 (resolve some terminology) 38 in Bugs.md
• Fix Issue 30 - 39 in Bugs.md
• Fix Issue 20 - 40 in Bugs.md
• Fix Issue 12 - 41 in Bugs.md (dump + events over socket)
• Fix Bugs found via scan-build static analysis (42 - 45 in Bugs.md)
• Fix Issue 33 - 46 in Bugs.md
• Fix Issue 32 - 47 in Bugs.md
• Fix Issue 16 - 48 in Bugs.md
• Fix Issue 3 - 49 in Bugs.md (disabling keybinding interpretation for specific keyboards is now possible)
• Fix Issue 26 - 50 in Bugs.md
• Fix Issue 7 - 51 in Bugs.md (Change cursor to square while Cagebreak is waiting for a key)
• Fix config bug for some commands - 52 in Bugs.md
• Fix Issue 35 - 53 in Bugs.md (update to wlroots 0.16.1)
• Improve FAQ.md (related to some Issues)
• Disable outputs when unable to set any mode (crashed previously)
• Add Code of Conduct
• Print version number on startup