Matomo image restored

A while ago, the Bitnami Matomo Docker image (docker.io/bitnami/matomo:5) became unavailable which broke analytics for deployments that were using the matomo-enabled profile. The issue is now fixed.

As part of work on another privately-sponsored grant managed by the FPA, Amritpal Singh replaced docker.io/bitnami/matomo:5 with the official matomo image from Docker Hub (matomo:5.8.0-apache or matomo:latest).

He also updated environment variables and volume mappings to match official image schema and ensured compatibility with existing Matomo database schema and matomo-db (MariaDB).