Major rework and restructure

.gitignore

.gitlab-ci-server.yml

CONTRIBUTING.md

README.md

cmd/stream-server/main.go

docs/about/changelog.md

docs/about/contributing.md

docs/android-integration.md

docs/assets/StreamServerClient.java

docs/changelog.md

docs/download-and-run.md

docs/index.md

docs/options.md

docs/quickstart.md

docs/reference.md

go.mod

go.sum

internal/api/twitch.go

internal/server/display.go

internal/server/server.go