docs: point the community section at Discussions, and drop an orphaned blog page - #9

Changed pages include:

• index.html - view
• blog/index.html - view
• changelog/index.html - view
• configuration/index.html - view
• example/index.html - view
• getting-started/index.html - view
• migration/index.html - view
• projects/index.html - view
• rules/index.html - view
• troubleshoot/index.html - view

There are more changes not included in the list