[Docusaurus] Adding docker deployment files

Summary: Adds same files that exist for cashtab deployment to docs. Changed container name in docker-compose.yml

Test Plan:

docker build --no-cache -t docs .
docker run -it -p 9000:80 docs

Navigate to localhost:9000 in web browser to see deployment

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D9174