docs/build.md: Emphasize JDK requirements + formatting
docs/build.md: Emphasize JDK requirements + formatting

* docs/build.md describes how to build Bisq, so steps are part of one
  process. Use bullet points instead of headings to emphasize this fact.
* Use Markdown formatting to indent parts of bullet points for better
  and clearer visual appearance.
* Provide Windows instructions the same way instructions for Linux and
  macOS are provided

bisq-network/exchange,bitsquare/bitsquare,bitsquare/bitsquare,bisq-network/exchange