make icons themeable

data/gnome-shell/pamac-updates@manjaro.org/extension.js

data/icons/hicolor/16x16/status/package-available-locked.svg

data/icons/hicolor/16x16/status/package-available.svg

data/icons/hicolor/16x16/status/package-install.svg

data/icons/hicolor/16x16/status/package-installed-locked.svg

.../icons/hicolor/16x16/status/package-installed-updated.svg

data/icons/hicolor/16x16/status/package-reinstall.svg

data/icons/hicolor/16x16/status/package-remove.svg

data/icons/hicolor/16x16/status/package-upgrade.svg

data/icons/hicolor/24x24/status/pamac-tray-update.svg

resources/package-available-locked.svg

resources/package-available.svg

resources/package-generic.svg

resources/package-install.svg

resources/package-installed-locked.svg

resources/package-installed-updated.svg

resources/package-upgrade.svg

resources/pamac.manager.gresource.xml

src/manager_window.vala

src/tray.vala