feat: add visible RSS/Atom feed links to navbar and footer - #406

Changed pages include:

• index.html - view
• 404.html - view
• blog/index.html - view
• community/index.html - view
• contributors/index.html - view
• events/index.html - view
• maintainers/index.html - view
• markdown-page/index.html - view
• projects/index.html - view
• resources/index.html - view

There are more changes not included in the list