Add includeTypes attribute to support component instance

[marcomontalbano]

Refers to #151

This PR aims to add the ability to include INSTANCE components to the export. By default, all COMPONENTs are exported, but now you can add the property includeTypes to the .figmaexportrc.js file:

...

['components', {
    fileId: 'fzYhvQpqwhZDUImRz431Qo',
    onlyFromPages: ['empty-page', 'icons', 'unit-test'],
    includeTypes: ['COMPONENT', 'INSTANCE'],
    ...
}]

Exporting via CLI is straightforward:

figma-export components fzYhvQpqwhZDUImRz431Qo -O @figma-export/output-components-as-svg -t INSTANCE