Closes#1847.
## Demo
### Production
https://swarmgame.net/list-games.html
### Local testing
```
tournament/scripts/demo/server-native.sh
```
and
```
scripts/test/run-tests.sh swarm:test:tournament-host
```
## Authentication flow
1. Users are represented by a GitHub username (primary key) and an "authentication cookie" in the SQLite database.
2. Site prompts user to login when the client's cookie is nonexistent or does not match any user in the database.
3. GitHub flow:
1. Clicking the "Login" link redirects user to the GitHub login page.
2. GitHub sends a `code` to our callback URL.
3. use that `code` to get an "access token"
4. use the "access token" to look up the username of the person who is logging in.
5. generate and store a new cookie in the database row for that username
6. set the cookie value on the user's client.
4. As long as the client keeps sending the cookie value known to the server, all uploads/activity will be attributed to their GitHub username.
## New features
* Login/Logout
* All uploaded content is attributed to an authenticated GitHub user
* Separate pages for scenario lists and solution lists
* Download a solution file
This is a rework of #1798 to facilitate a simpler web stack.
# Demo
View http://swarmgame.net/
NOTE: Requires IPv6
# Motivation
Hosting cost is a main motivation. Cost per month for an EC2 instance, RDS, and the requisite other services approaches >$50 per month. In contrast, the lowest-tier Lightsail instance is $3.50/month.
The deployment process is of course simplified.
An incidental benefit to using SQLite is reduced latency of web requests; we no longer need to fetch credentials from an AWS API to connect to Postgres.
## Changes
Major changes:
* Use `sqlite` instead of `postgres`
* Use Docker to build a statically-linked deployable binary, rather than deploying the app within a Docker image
Fortunately, the API of `sqlite-simple` is near-identical to that of `postgresql-simple`, so most of the code change there is just to rip out AWS-specific stuff and Postgres connection info. I have no hesitation to delete this code since if we ever want to use the previous stack again, we can just look at #1798.
