Fix the issues on Signup/login page

[supriya3105]

First name - Add validation that only alphabets can be entered. No numbers and special characters are allowed. Also the fields cannot be blank. So we need to show the * sign against the field.
Change the error message, position and format displayed when
1. Valid email address is not entered
2. Password are too short
3. Passwords do not match.
Change the content of email received to verify the email address after signing up.

[supriya3105]

@AkashKale Please come up with the design to display the error message at the top of the page above the signup form. Currently this is how they are being displayed.

Not on priority but this should be incorporated.

[AkashKale]

Mockup for signup form validation - https://www.figma.com/file/4gdPDRPqGqQqPYsO3Qj8CG/Miru-App?node-id=966%3A9308