LibGUI: Give some widgets a reasonable default fixed height

Instead of hard-coding 22 in random places, just make the following
widgets have a fixed height of 22 by default: Button, CheckBox,
ColorInput, ComboBox, RadioButton, SpinBox, TextBox.

In the future we can make this relative to the current font size,
but for now at least this centralizes the setting a bit better.

Libraries/LibGUI/Button.cpp

@@ -38,6 +38,7 @@ namespace GUI {
 Button::Button(String text)
     : AbstractButton(move(text))
 {
+    set_fixed_height(22);
     set_focus_policy(GUI::FocusPolicy::StrongFocus);
 }