Add new tags and community announcement for LFX Mentorship - #706

Changed pages include:

• index.html - view
• 404.html - view
• blog.html - view
• case-studies.html - view
• changelog.html - view
• community.html - view
• docs.html - view
• events.html - view
• search.html - view
• tutorials.html - view

There are more changes not included in the list