Add Qt annotations

[pterror]

Tested both by adding all .xml interface files to a Qt project via qt_add_dbus_interface, and through meson test -C _build.

Two tests are failing, attached for posterity:
testlog.txt
They don't seem to be introduced by this PR though, as I can still reproduce them on the previous commit, even after a clean rebuild.

Note that Lockdown.xml still errors as its property names are kebab-cased instead of snake_cased, which Qt considers as invalid.

• Add missing Qt type annotations for complex types
• Reorder Qt type annotations to the line above their corresponding parameters for consistency
• Fix incorrect argument names

Also does minor formatting changes for consistency:

• Prefer double quotes over single quotes
• Prefer type= before name= before direction=
• Make implicit direction="in" explicit?

[pterror]

Upon trying to actually compile the Qt project, it seems like the arguments named namespace in Settings.xml cause issues in the C++ that Qt generates.

Probably not relevant here though as it's probably something that should be fixed on Qt's side.

[davidedmundson]

The annotations look correct.

[davidedmundson]

a{sv} isn't needed to be special cased, which makes up a lot of these changes.

[swick]

We already have a whole bunch of those annotations where a{sv} is annotated with a QVariantMap. Could we remove all of them?

[swick]

@pterror do you know why the annotations on a{sv} exist and why @davidedmundson claims they are unnecessary?

[swick]

The changes from ' to " for consistency are a great cleanup. Can you split them into their own commit?

[pterror]

test results:

Summary of Failures:

 2/30 xdg-desktop-portal / test-doc-portal                    ERROR            0.21s   killed by signal 6 SIGABRT
 9/30 xdg-desktop-portal:portals / test-portals-location      ERROR            0.27s   killed by signal 6 SIGABRT
12/30 xdg-desktop-portal:portals / test-portals-openuri       ERROR            0.26s   killed by signal 6 SIGABRT
10/30 xdg-desktop-portal:portals / test-portals-notification  ERROR            0.67s   killed by signal 6 SIGABRT

Ok:                 26  
Expected Fail:      0   
Fail:               4   
Unexpected Pass:    0   
Skipped:            0   
Timeout:            0  

test-doc-portal and test-portals-location were already failing since last time.
i can confirm the two new failures are still present in 840fd1d0e14b5d2e7292bdfc1cbc94e8e0a8b0ef so it should not be a regression introduced by this PR

[swick]

We upgraded the CI. Try rebasing to get it green.