chore: Make icon installations more dynamic in the Makefile (#243)

Some new icons color set for the systray applet will be added soon and we are planning to make additional users contributed colors as easy as possible to implement (see #240). 
Adopting a more "dynamic" way to install icons in the Makefile will avoid having to modify it each time a new icons color set is added.

Makefile

@@ -15,8 +15,8 @@ install:
 	install -Dm 755 src/lib/* -t "${DESTDIR}${PREFIX}/share/${pkgname}/lib/"
 
 	# Install icons
-	install -Dm 664 "src/icons/${pkgname}.svg" "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/${pkgname}.svg"
-	install -Dm 664 "src/icons/${pkgname}_updates-available.svg" "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/${pkgname}_updates-available.svg"
+	install -Dm 664 src/icons/"${pkgname}"*.svg -t "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/"
+	install -Dm 664 src/icons/"${pkgname}"_updates-available*.svg -t "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/"
 
 	# Install .desktop files
 	install -Dm 644 "res/desktop/${pkgname}.desktop" "${DESTDIR}${PREFIX}/share/applications/${pkgname}.desktop"
@@ -62,11 +62,11 @@ uninstall:
 	rm -f "${DESTDIR}${PREFIX}/bin/${pkgname}"
 
 	# Delete data folder (which stores libraries)
-	rm -rf "${DESTDIR}${PREFIX}/share/${pkgname}"
+	rm -rf "${DESTDIR}${PREFIX}/share/${pkgname}/"
 
 	# Delete icons
-	rm -rf "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/${pkgname}.svg"
-	rm -rf "${DESTDIR}${PREFIX}/share/icons/hicolor/scalable/apps/${pkgname}_updates-available.svg"
+	rm -f "${DESTDIR}${PREFIX}"/share/icons/hicolor/scalable/apps/"${pkgname}"*.svg
+	rm -f "${DESTDIR}${PREFIX}"/share/icons/hicolor/scalable/apps/"${pkgname}"_updates-available*.svg
 
 	# Delete .desktop files
 	rm -f "${DESTDIR}${PREFIX}/share/applications/${pkgname}.desktop"