Remove the server code and related artifacts

[thekaveman]

Update:

• the server service to use the image from Add GitHub Action to build/publish Docker image eligibility-server#7

Remove:

• debug config in .vscode/launch.json
• server.json entry in .gitignore
• bandit exclude in .pre-commit-config.yaml
• runServices entry in .devcontainer.json
• localhost/data/server.json
• localhost/keys/server.key (we still need the public key)

Edit: we actually want to keep the runServices entry, since we want the server starting up for the devcontainer, by default.