Add Docker support

[blabno]

No description provided.

[mrosseel]

looks good, one remark - for the seednodes I've been doing some docker work as well, and I've now partially switched from using the startApi.sh style and directly putting the arguments in docker-compose, using the 'command:' feature. These get added to the end of the entrypoint, which can be gradlew in this case. Futhermore, the values of these arguments can be hard-coded as now or defined in a .env file, so that the user doesn't have to touch the docker-compose.yml. This would eliminate the shell script and avoid having to change in two places if an argument changes/gets added. For an example see the btcd service in my seednode branch

[blabno]

@mrosseel I still see bash script to start: https://github.com/mrosseel/bisq/blob/dao-seednode/seednode/docker/prod/Dockerfile#L25

[blabno]

I'm open to experimenting in future, however since approach in this PR works I would like to proceed this way to get something usable for users.

[mrosseel]

@mrosseel I still see bash script to start: https://github.com/mrosseel/bisq/blob/dao-seednode/seednode/docker/prod/Dockerfile#L25

yes, as mentioned I use the technique for the btcd service. Not a blocking thing, but certainly a TODO to remove the unnecessary script.

utACK