[Header Area] Design and Styling enhancements on the header area

[ElinorW]

The header area needs some design, styling and layout enhancements to make it intuitive, responsive and accessible.
Tracking these here.

• Task: page layout #1683
• Task: Profile callout styles #1686
• Make sample queries, history items and resources cover the full sidebar length Task: Extend sidebar content space #1709
• Fix: panel overlay #1714
• Remove scrollbar from the settings items
• When signing in, the spinner and 'signing you in' message are not properly aligned

• Bottom part needs some alignment
• Add a border around the sidebar component
• Add an icon on Tenant info part
• Add hovering effect on the header buttons
• Move high contrast option to be on the same line as light/dark mode in the dialog #1738
• Fix: Restore permissions styles #1761
• Task: Limit sidebar resize #1769
• Task: tenant name ellipsis #1799 - Breaking change. Reverted

[Onokaev]

#1682