`aqt list-qt`: Remove `--extension`/`--extensions` options

[ddalcino]

Is your feature request related to a problem? Please describe. This is a UI/UX problem that I have with the aqt list-qt interface.

I think that the --extension flag should not be necessary to list architectures, modules, and archives. It's easy to forget that you need to use this flag. This flag is not necessary when using install-qt because the install-qt command is able to figure out which extension is necessary on its own. Why should list-qt be different?

If I am trying to list architectures using aqt list-qt linux desktop 5.15.2, I think it would be natural to expect list-qt to list every architecture available (gcc_64 and wasm_32). I do not expect to have to pass --extension wasm in order to find out that wasm_32 is an available architecture.

Describe the solution you'd like This is what I would like aqt list-qt to do when I use these CLI commands, without having to use the --extension flag:

$ aqt list-qt linux desktop --arch 5.15.2
gcc_64 wasm_32
$ aqt list-qt linux android --arch 6.0.0
android_x86_64 android_x86 android_armv7 android_arm64_v8a
$ aqt list-qt linux android --modules 6.2.0 android_armv7
qt5compat qtquick3d qtquicktimeline qtshadertools ...
$ aqt list-qt linux android --archives 6.2.0 android_armv7
qtbase qtdeclarative qtquickcontrols2 qtsvg qttools qttranslations ...

All of the above commands currently either fail or report the wrong results, because the user has omitted the --extension flag.

Describe alternatives you've considered I have tried using the existing interface. I think it's cumbersome and not fun to use.

Additional context This will be an interface-breaking change. If anyone is using the --extension flag and parsing the output in an automated script, they will need to be warned about this.

This change will remove some functionality from list-qt. It is hard for me to imagine that any of our users are relying on these features, though.

• Currently, you can list all versions of Qt that have a particular architecture with:

  aqt list-qt <host> desktop --extension wasm     # show all versions that have the wasm_32 arch
  aqt list-qt <host> android --extension arm_v7   # show all versions that have the android_arm_v7 arch
  

  This capability will disappear, unless a new interface is added.
• Currently, you can list all preview versions of Qt available on download.qt.io, even though aqt is not capable of installing them:

  aqt list-qt linux desktop --extension preview
  aqt list-qt linux desktop --extension wasm_preview
  

  I don't see a need to keep this functionality, unless we plan to allow aqt to install preview versions.