Analytics: migrate to GA4

[chalin]

This as part of a CNCF-wide effort to upgrade project websites to GA4. For context, see:

• Migrate CNCF websites to GA4 cncf/techdocs#108

Tasks (stages 1 & 2):

• Prep: Exclude analytics from non-production builds #1002
• Create a GA4 tag (measurement ID) --> G-8H17ZWYV40
  Notes:
  • Console
  • UA and GA4 tags are now connected
  • CNCF is admin
• Stage 2: Analytics: configure GA4 ID as main id #1003

Followup:

• Stage 3: Analytics: switch to using GA4 site tag only and UA via connected config #1009

Context:

• Migrate CNCF websites to GA4 cncf/techdocs#108

[chalin]

All done!