Re-arrange TODOs.
Extract methods initialize_page() and create_css_settings_control().
Extract methods preset_button() and reset_button().
Remove data-type attribute from settings controls.

May add it back later but removed it for the time being
as 'range' is the value used at the moment.
Extract function settings_controls().
Extract function extract_setting_specs().
Extract function create_attribute_label().
Extract function create_input_control().
Extract function create_units_label().
Extract function create_range_control().