Add Dockerfile: minimize docker image by using nginx (alpine)

[cuongtransc]

Dockerize elasticsearch-head and serve by nginx.

1. Support HTTP Basic Authentication, default parameters:

• USERNAME=elasticsearch
• PASSWORD=elasticsearch@123

2. Connect ElasticSearch Server, don't need to enable http.cors.allow-origin on elasticsearch.
   Default parameters:

• ES_HOST=172.17.0.1
• ES_PORT=9200

Build:

docker build -t cuongtransc/elasticsearch-hq:5.0 .

Run:

docker run \
    --name esh \
    -p 8080:80 \
    -e HOST=es.example.com \
    -e PASSWORD=elasticsearch@123 \
    -e ES_HOST=172.17.0.1 \
    -e ES_PORT=9200 \
    cuongtransc/elasticsearch-head:5-alpine

Access: http://es.example.com:8080/index.html?http://es.example.com:8080/

The Docker Image size is 17.2 MB! (Compressed Size is 7 MB).

Docker Image: https://hub.docker.com/r/cuongtransc/elasticsearch-head/tags/