Include default config in docker image

[groldan]

Fixes #46

Externalized default configuration:

Include the configurable properties as a file in the Docker image under /etc/geoserver/acl-service.yml

This has some default values and makes clear which config properties should/cloud be overridden as environment variables in deployment files.

Full list of configurable properties:

These are shortenerd property names used in ${} placeholders in the embedded application.yml, and meant to be easily translated to environment variables (e.g. pg.host -> PG_HOST):

pg.host: acldb
pg.port: 5432
pg.db: acl
pg.schema: acl
pg.username: acl
pg.password: acls3cr3t
pg.pool.min: 2
pg.pool.max: 50
pg.pool.connectionTimeout: 3000
pg.pool.idleTimeout: 60000

acl.security.basic.enabled: true
acl.users.admin.enabled: true
acl.users.admin.password: "{bcrypt}$2a$10$eMyaZRLZBAZdor8nOX.qwuwOyWazXjR2hddGLCT6f6c382WiwdQGG"
acl.users.geoserver.enabled: true
acl.users.geoserver.password: "{noop}s3cr3t"
acl.security.headers.enabled: false
acl.security.headers.user-header: sec-username
acl.security.headers.roles-header: sec-roles
acl.security.headers.admin-roles: ["ROLE_ADMINISTRATOR"]

Sample docker compose.yml file:

version: "3.1"
services:
  acldb:
    image: postgis/postgis:15-3.3
    environment:
      - POSTGRES_DB=acl
      - POSTGRES_USER=acl
      - POSTGRES_PASSWORD=acls3cr3t

  acl:
    image: geoservercloud/geoserver-acl:2.0-SNAPSHOT
    environment:
      - PG_HOST=acldb
      - PG_PORT=5432
      - PG_DB=acl
      - PG_SCHEMA=acl
      - PG_USER=acl
      - PG_PASSWORD=acls3cr3t
    ports:
      - 8080:8080
      - 8081:8081