This should avoid:
```
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid-git/contents/ui/main.qml:13:34: QML FullRepresentation: Binding loop detected for property "implicitWidth"
…
qml: PlasmaExtras.ScrollArea is deprecated. Use PlasmaComponents3.ScrollView instead.
…
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid-git/contents/ui/TabButton.qml:27:13: Unable to assign [undefined] to QFont
…
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid-git/contents/ui/ToolButton.qml:23:13: Unable to assign [undefined] to QFont
```
This should prevent the following warnings:
```
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:284:17: QML DevicesPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:287:17: QML DownloadsPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:290:17: QML RecentChangesPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:281:17: QML DirectoriesPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:284:17: QML DevicesPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:287:17: QML DownloadsPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
file:///usr/share/plasma/plasmoids/martchus.syncthingplasmoid/contents/ui/FullRepresentation.qml:290:17: QML RecentChangesPage: Detected anchors on an item that is managed by a layout. This is undefined behavior; use Layout.alignment instead.
```
See https://github.com/Martchus/syncthingtray/issues/133
* Use header (with integrated buttons when shown as part of the system tray
Plasmoid)
* Use less space so it fits into the system tray plasmoid (at least on a
full HD screen with 96 dpi)
* Show action for internal errors only if there are internal errors (like
in the Qt Widgets based GUI)
* Port away from deprecated tab bar (which is not used in official
Plasmoids anymore as well)
* Simplify code for ensuring the minimum size as configured (still does
not work within the system tray Plasmoid)
It fits better than "view-barcode" from the icon theme. This also tests
using ForkAwesome icons via the custom icon engine. Unfortunately this
does not seem to work within the Plasmoid so far.
* FontAwesome uses a propritary build system so let's move to its fork
ForkAwesome similar to Syncthing
* See https://github.com/syncthing/syncthing/pull/5237
* Bundle the font file instead of having the SVGs directly within
Syncthing Tray's own repository
Loading the icon for the button from resources ceased to work (maybe when
switching to `PlasmaComponents3.ToolButton`). This change works around the
problem and the old icon no longer needs to be bundled.
