Theme customizer – can’t add section/settings

Your use of add_control is incorrect. More specifically, you are not telling what type of control you want to add. Refer to the codex link to see which types can be generated automatically. I’ve given an example with a text field below.

$wp_customize->add_control('cta_heading', array(
    'label' => __('CTA Heading','starter'),
    'section' => 'home_call_to_action_section',
    'setting'=>'home_call_to_action_setting_section',
    'type'=>'text',
));  

Beware that if you want more complex controls, such as colours, you need to explicitly create the control object. An example is given in the codex link as well.