Remove obsolete dojoup shell installer

[kronosapiens]

The dojoup/dojoup shell script is the legacy installer that downloads and manages dojo binaries directly.

Now that the toolchain has moved to asdf-based installation (dojoup/install), the old dojoup/dojoup script and its associated infrastructure should be cleaned up:

• dojoup/dojoup - the legacy shell installer
• Any related CI/packaging that only serves the old installer

The asdf plugins (asdf-sozo, asdf-katana, asdf-torii, asdf-saya) now handle installation individually.