Move Keycloak configuration to script

[eleftherias]

Fix #1151

[eleftherias]

@JAORMX It would be great if you could try make identity locally because you have a different setup.

[JAORMX]

Love that we no longer carry that big config file. I wonder if we could replace the multiple exec calls with a single init script thay we could set as the container's entrypoint.

[eleftherias]

I wonder if we could replace the multiple exec calls with a single init script thay we could set as the container's entrypoint.

@JAORMX We could, but we would require an extra step anyway for users to set their github client credentials for social login. Either setting them in a file or environment variable.
The entrypoint script would also have to have a wait / sleep step until the container is healthy, because it starts executing too early.

[JAORMX]

@eleftherias worked like a charm! Let's add docs to mention you need now a two step process to test this out. Otherwise it's good to go. I'd still like this to be a one-step process but we can optimize later on.

[eleftherias]

@JAORMX I ended up going with your suggestion and moving the exec calls into the entrypoint, except for the GitHub login. Now Keycloak is set up with the realm and clients when running docker-compose up -d keycloak and then GitHub login is optionally set up when running make KC_GITHUB_CLIENT_ID=<client_id> KC_GITHUB_CLIENT_SECRET=<client_secret> github-login.

[JAORMX]

worked for me!