service/upower: add upower service

[bdebiase]

Adds a UPower service to interact with system battery devices. I only implemented properties I thought would be useful, but more can be added later on.

This is my first shot at C++ so any suggestions would be greatly appreciated!

[outfoxxed]

Thanks a lot!

Looks pretty good overall, just a few UAFs and nitpicks.

[outfoxxed]

Noticed a few more things while testing.

Here's my tester if you don't have one, but I assume you do

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts
import Quickshell
import Quickshell.Services.UPower

ShellRoot {
	Component {
		id: comp

		Rectangle {
			required property var modelData;

			implicitWidth: layout.implicitWidth + 10
			implicitHeight: layout.implicitHeight + 10
			color: palette.active.base

			ColumnLayout {
				id: layout

				Label { text: `is display device: ${modelData == UPower.displayDevice}` }
				Label { text: `device type: ${UPowerDeviceType.toString(modelData.type)}` }
				Label { text: `is power supply: ${modelData.powerSupply}` }
				Label { text: `energy: ${modelData.energy}` }
				Label { text: `energy capacity: ${modelData.energyCapacity}` }
				Label { text: `change rate: ${modelData.changeRate}` }
				Label { text: `time to empty: ${modelData.timeToEmpty}` }
				Label { text: `time to full: ${modelData.timeToFull}` }
				Label { text: `percentage: ${modelData.percentage}` }
				Label { text: `is present: ${modelData.isPresent}` }
				Label { text: `state: ${UPowerDeviceState.toString(modelData.state)}` }
				Label { text: `health percentage: ${modelData.healthPercentage}` }
				Label { text: `health supported: ${modelData.healthSupported}` }
				Label { text: `icon name: ${modelData.iconName}` }
				Label { text: `is laptop battery: ${modelData.isLaptopBattery}` }
			}
		}
	}

	FloatingWindow {
		color: contentItem.palette.active.window

		ListView {
			anchors.fill: parent
			spacing: 10

			model: UPower.devices
			delegate: comp
		}

		Loader {
			anchors.right: parent.right
			active: UPower.displayDevice != null

			sourceComponent: BoundComponent {
				sourceComponent: comp
				property var modelData: UPower.displayDevice
			}
		}
	}
}

[outfoxxed]

After this please squash+rebase and it should be good to merge.

[outfoxxed]

LGTM, thanks!

[bdebiase]

Thanks for everything!