Include a mechanism to set local timezone

[Goro2030]

It would be great if one could pass the local timezone variable to the container to use, especially handy for the bitcoin debug.log.

For this to work , it requires the tzdata package installed in the image, according to this wiki article.

Then the user would pass an environment variable in compose:

environment:
      - TZ=America/Santiago

or a -e in the docker command line.

[nolim1t]

Thanks will consider it in the next build

[nolim1t]

Or maybe symlinking /etc/localtime might work better too as there would be less moving parts in the container?