chore(readme): improve structure and content

[nijikokun]

Changelog:

• Updated introduction to be streamlined introduction of the project and capabilities.
  • Future task: create an exhaustive list of feature-sets below overview.
• Added table of contents to the top of the readme with important links
• Added a note about helm being recommended way for installation over manifest
• Merged Helm and YAML manifests installation into single section
• Changed notes to use new Github note callout feature
• Changed repository images to take up less space and left aligned content
• Changed it so all badges are on the same line
• Changed code blocks from bash to sh to enable code highlighting
• Moved account requirement to top of the readme for better visibility
• Moved warning to known issue section