Lighthouse performance

[milliorn]

This PR is to fix issues Chrome DevTools Lighthouse found in its audit. On the left side of the image is before, on the right is after.

https://developer.chrome.com/docs/lighthouse/performance/render-blocking-resources/?utm_source=lighthouse&utm_medium=devtools#how-to-eliminate-render-blocking-stylesheets

https://web.dev/optimize-cls/?utm_source=lighthouse&utm_medium=devtools#images-without-dimensions

https://developer.chrome.com/docs/lighthouse/performance/font-display/?utm_source=lighthouse&utm_medium=devtools

https://perfmatters.io/docs/ensure-text-remains-visible-during-webfont-load/#font-awesome

https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel/preload#the_basics

[AnilSeervi]

Thanks you for you suggestions @milliorn. I've made the these changes and other required changes in #5