Docker: exclude postgres14, mail containers based on .env

[matthew-white]

Rather than manually removing postgres14 and mail from docker-compose.yml when they are not needed, can we exclude them based on the variables in .env? That would make configuration easier for users. It would also reduce the number of merge conflicts that the ODK team has to resolve on staging.

CC @sadiqkhoja

[sadiqkhoja]

there are few options to achieve this:

• Create a custom bash script to start/stop docker containers based on .env file
• Add one or more profiles in docker-compose.yml and then run docker compose with a particular profile. There can be few permutations to tackle with this approach.
• Just start cloud servers with docker compose up --scale postgres14=0 --scale postgres=0 --scale mail=0 -d and add this trick in documentation as well.