Add an onboarding modal

[samanyougarg]

Let's add an onboarding modal where we ask for user's name and email.
This should be a required field to proceed to the next step. And we will use this to:

1. Personalize the message
2. Send "Shloka of the day" emails and newsletters

[Gupta-Anubhav12]

Let's also save the onboarding in a cookie/local storage to persist it

[samanyougarg]

Yess!