Added Github Repo Link on Nav with Icon

[designMoreWeb]

What's this PR do?

• Added Font awesome Github Alt icon
• Added link to this repo
• Fixes the issue of not having a Github repo link in the navigation bar

  Where should the reviewer start?

• Run the page and check if the github icon appears and if the link works correctly

  How should this be manually tested?

• Manually go to the page and test the icon/link

  Any background context you want to provide?

• None

  What are the relevant tickets?

• Fixes issue #57 [https://github.com/ladybug-podcast/ladybugpodcast/issues/57]

[designMoreWeb]

My pleasure :)