Document -all and -replica endpoints for HA/DG3

[remilejeune2]

Where on docs.platform.sh should be changed?

https://docs.platform.sh/add-services/mysql.html
https://docs.platform.sh/add-services/postgresql.html

What exactly should be updated?

On HA / DG3, mariadb and postgresql expose multiple endpoints to let the user consume the service in different ways:

all: list of all endpoints, including, main and replicas
replica: list all replica endpoints.

Note: we need to check if -all is only for Mariadb or also available on postgresql

Additional context

No response

[chadwcarlson]

Thread suggests all is only available for Postgres, not MariaDB