Capture style tips and conventions as GitHub issues

[cbeams]

This first style guide issue is rather meta. It is a style guide entry about how to build our style guide over time.

Whenever you are dealing with matters of style and convention in Java, Git, GitHub, Slack and the other tools we use together to build Bisq, consider capturing them here in this repository as a GitHub issue. Doing so has a few benefits:

1. It provides a natural place for a conversation to ensue about that style guide entry, and for a rough consensus to form about it.

2. It provides an easily linkable resource for future use, so that style tips don't need to be repeated everywhere. If you're reviewing someone else's work, or refactoring something, you can simply use a GitHub issue reference to the style guide entry in question, e.g. this one, which is Capture style tips and conventions as GitHub issues #1.

When a style guide issue has been around for a while and has rough consensus, it can graduate to a written entry in the README.adoc file in the root of this repository, and the issue can be closed.