Add dev-qt from an older version of the gentoo repo

Qt5 has been removed, we restore it since we still use it.

dev-qt/qtwebengine/metadata.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="project">
+		<email>qt@gentoo.org</email>
+		<name>Gentoo Qt Project</name>
+	</maintainer>
+	<use>
+		<flag name="designer">Install the QWebEngineView plugin used to add widgets in <pkg>dev-qt/designer</pkg> forms that display web pages.</flag>
+		<flag name="jumbo-build">Combine source files to speed up build process.</flag>
+		<flag name="pdfium">Build the QtPdf module based on chromium's PDFium library</flag>
+		<flag name="qml">Build QML/QtQuick bindings and imports</flag>
+		<flag name="system-icu">Use the system-wide <pkg>dev-libs/icu</pkg> instead of bundled.</flag>
+		<flag name="webdriver">Build tool for automated testing (ChromeDriver equivalent)</flag>
+		<flag name="widgets">Enable QtWidgets support</flag>
+	</use>
+	<upstream>
+		<bugs-to>https://bugreports.qt.io/</bugs-to>
+		<doc>https://doc.qt.io/</doc>
+		<remote-id type="github">qt/qtwebengine</remote-id>
+		<remote-id type="github">qt/qtwebengine-chromium</remote-id>
+	</upstream>
+	<slots>
+		<subslots>
+			Must only be used by packages that are known to use private parts of the Qt API.
+		</subslots>
+	</slots>
+</pkgmetadata>