Add 'Export All' feature

We would like to add a feature that exports all layers. The export modal is currently using USWDS Card Component to house the text and button. We want to change this to show 2 cards, one on the left for exporting current layers (this is functionality we already have), and one on the right for exporting all layers.

1. Edit the Export Modal to have two cards.
2. On the left card:
   • edit the current title to say 'Export All Active Layers'
   • edit the current button to say 'Export active layers'
3. On the right card,
   • add a title that says 'Export All Layers'
   • add text that says 'Export an Excel file of metadata information for all layers available in the mapper. Each layer will have a single row containing the metadata information available for the layer.'
   • add a button that says 'Export all layers'
4. Add functionality to the 'Export all layers' button click. When a user clicks the button, we want to export an Excel sheet of the information found in the config.json file. The information we want to include is: name, url, aboutPage, state, category, and subCategory. Each of these will be a column in the Excel file. This code can be added to the export.service.ts