Add 'Your Gateway to Crypto' Tagline to Footer

[akshay0611]

Summary:

• This PR introduces a tagline to the footer's brand section to clarify and emphasize the purpose of Cryptex as an entry point for cryptocurrency exploration.

Changes Made:

• Added a with the class tagline and the text "Your Gateway to Crypto" to the footer-brand div.
• The tagline is placed after the logo text with a line break for better readability.

Testing:

• Visually inspected the footer to ensure the tagline integrates well with the existing design.
• Checked that all links in the footer are still functional.
• Verified that the contact information is correctly displayed.

It closes Issue No #14

Please review and merge if the implementation meets the project's standards.