Outage pages cleanup

• Remove outdated exclamation mark image and replace it with more modern looking icon created by a designer at DoIT Comm
• Delete unused simple.js file, that included outdated/unused code
• Add missing html language specification
• Remove inline style code and add reference to the styles included in a stylesheet file
• Add missing alt text to the UW Logo
• Heading level fix
• Fix alignment of items in header on mobile view