Figma: Add missing Get.gov pages to Figma file and create cover page

[rileyorr]

Issue description

There are some missing Get.gov pages that the design team would like mocked up. The 'Choosing your domain' page and the 'Moving to .gov' should be mocked up. The remaining pages that are listed as 'New mockup' in the spreadsheet should be indicated on the Get.gov cover page and the Google Docs linked.

Pages that need to be added per the audit spreadsheet:

• Choosing your domain name (Row 11)

Acceptance criteria

• [ ] The existing 'Choose your domain' art boards under Mocks/1221 & 1219 are brought onto their own page
• [ ] Add rest of the content from the dev page
• [ ] Double check styling
• [ ] Update notes to align with the rest of the pages
• [ ] The Get.gov pages that aren't mocked up are listed on the cover page with Google Docs linking to them
• [ ] Gaby has reviewed the Figma branch and updates have been added to the main file

Additional context

No response

Links to other issues

No response

[rileyorr]

@gabydisarli and I met and decided that not all the missing pages should be mocked up. This issue's description was updated on 4/30 to reflect the work to be done.