Fix: Padding,typos & HTML Tags

[srijan2607]

This pull request primarily updates external links to use secure HTTPS URLs, corrects typos and minor content errors, and improves the site’s layout and accessibility. It also updates copyright years and footer information.

Link and Content Corrections:

• Updated all external links throughout the site to use HTTPS instead of HTTP, improving security and reliability. This includes project references, acknowledgements, and gateway links. [1] [2] [3] [4] [5] [6] [7] [8]
• Fixed typos and improved clarity in documentation and API descriptions (e.g., "Existance" → "Existence", "easilly" → "easily", "occured" → "occurred", "idetifier" → "identifier", "existancy" → "existence"). [1] [2] [3] [4]
• Corrected minor content errors, such as fixing the spelling of "LEAD Sience Gateway" to "LEAD Science Gateway" and removing stray or malformed HTML. [1] [2]

Accessibility and Layout Improvements:

• Added alt text to images for improved accessibility. [1] [2] [3]
• Improved page layout and footer styling by updating CSS to use flexbox, ensuring the footer stays at the bottom of the page and removing extra space after the footer. [1] [2]

Copyright and Legal Updates:

• Updated copyright year from 2021 to 2025 and ensured license links use HTTPS. [1] [2]