ADD insert commit hash into web and api images

# Putting commit in docker images

We can do this through the `GIT_TAG` environment variable from the makefile, that is passed to the docker-compose setup. We can add it as an environment variable. Pass this to the docker build by specifying it as a [docker build arg](https://docs.docker.com/engine/reference/builder/#arg) [in the docker-compose.yml file](https://docs.docker.com/compose/compose-file/build/#args). The `GIT_TAG` environment variable will be set when building through `make build`, so you can reference it in the docker compose file like this: `${GIT_TAG:-latest}`. This is a special way of referencing an environment variable, where if `GIT_TAG` is not set, it will default to `latest`.

You can make these environment variables available when the docker image builds by converting the build arg to [an environment variable](https://docs.docker.com/engine/reference/builder/#env).

For example:

```dockerfile
ARG GIT_TAG=latest # default to latest
ENV GIT_TAG=${GIT_TAG} # convert build arg value to environment variable
```

# Exposing in services

## api
Then expose it throught the [healthcheck endpoint](https://github.com/AnubisLMS/Anubis/blob/main/api/anubis/utils/healthcheck.py) on the api.

## web
Expose it in the [footer of the website](https://github.com/AnubisLMS/Anubis/blob/main/web/src/components/shared/Footer.jsx). For the react website, you can see how to use an environment variable like this here https://create-react-app.dev/docs/adding-custom-environment-variables/ (basically just add `REACT_APP_` before the environment variable)