feat: thanks for sharing screen

[HelenGezahegn]

As a user, I want to share the app after finishing the registration process to raise awareness of the large worldwide community of people tracking their symptoms.

Acceptance Criteria

• It's done when there's a Thanks for sharing header and informational subheaders.
• It's done when there's a number indicating how many others have checked-in today.
• It's done when there's a Share now button available.
• It's done when upon clicking the Share now button, you are prompted to share a pre-defined message and link to the app on popular social media platforms.
• It's done when there's a Continue button available to navigate me to the next screen.

Additional Info

HowWeFeel App Inspo