ADDSRV-720-no-host-install

[KevinMind]

Relates to: ADDSRV-720

Description

This PR adds a preinstall script that ensures npm install is only run inside a docker container.

Additionally this PR moves the path for node_modules to the repository root in the docker container /data/olympia/node_modules and mounts this as a volume in the host repostory root.

Context

This prevents users from accidentally installing npm modules via the host which could lead to platform incompatibility errors.

when you run npm i on the host you'll get an error. If you run it in the docker container, it will install where the docker container expects.

Testing

[KevinMind]

Does this https://github.com/mozilla/test-github-features/pull/60 help here? Questioning the void.