Milestone 4

[svandragt]

Fixes #52. Fixes #51.

• Changes the default port to 80, facilitating commandline requests for static site generation
• changes the php-fpm port to 9090, to prevent conflicts with xdebug's default 9000 port.
• writes Caddy Server's access/error logs into the _logs folder.
• Runs PHP-FPM as root as to write cache files into the volume mounted as root.
• Update's the container's hostname to be identical to the local one (cuttlefish.test).
• Reads the /admin password environment variable via local docker-compose.override.yml.
• Makes the THEME_DIR constant available globally (specifically for view functions).
• Pages returned from cache are no longer also processed.
• Directories are no longer created if they already exist.
• When generating a static site:
  • theme assets are copied from the correct source path.
  • View functions are no longer included multiple times.
• Misc fixes.