Adding first and last name fields to About Editor

[etoledom]

Closes GRA-106

Description

This PR adds the First and Last name to the About Editor:

Testing Steps

• Run the Demo app
• Open the Quick Editor demo screen
• Select the About Editor scope
• Select all Extra input fields
• Open que Quick Editor
  • Check that the First and Last name fields are present inside the Extras group.
• Modify and save first and last name.
  • Check on Gravatar.com, on Accoutn settings, that the first and last name fields were modified.

Success 🎉

[wpmobilebot]

📲 You can test the changes from this Pull Request in Gravatar Prototype Build by scanning the QR code below to install the corresponding build.

	App Name	Gravatar Prototype Build
	Build Number	2373
	Version	PR #761
	Bundle ID	com.automattic.gravatar-sdk-demo-uikit.prototype-build
	Commit	447ee6c
	Installation URL	5fhqgja3i4o20

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[etoledom]

One extra change moving the footer message to the top of the group instead:

[pinarol]

Looks and works good 🎉