dbus-send: Add support for variants to arrays and dictionaries

Adds support for:
* Arrays of variants
* Dictionaries with variants as keys

Manually tested and confirmed working using dbus-monitor.
Example usage:
```
$ dbus-send --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus \
    com.example.SomeExample dict:string:variant:one,int16:1
```
In dbus-monitor:
```
method call time=1652796044.991509 sender=:1.84 -> destination=org.freedesktop.DBus
    serial=2 path=/org/freedesktop/DBus; interface=com.example; member=SomeExample
   array [
      dict entry(
         string "one"
         variant             int16 1
      )
   ]
```

Signed-off-by: Frederik Van Bogaert <frederik.vanbogaert@mind.be>
19 jobs for dev_add_variant_type_to_dbus_send in 21 minutes and 58 seconds (queued for 1 second)