Inconsistent Write Data > HTTP API site structure across `/influxdb3/` products

[jstirnaman]

Serverless: /influxdb3/cloud-serverless/write-data/api/v1-http/
Cloud Dedicated, Clustered: none (only CLI and Client libraries)
Core, Enterprise: Use the HTTP API
Enterprise has a duplicate v1 and v2 API compatibility link in the nav
Add alt_links for all if the structures differ