journal-remote: add documents in the unit files

journal: add minimal journal gateway daemon based on GNU libmicrohttpd This minimal HTTP server can serve journal data via HTTP. Its primary purpose is synchronization of journal data across the network. It serves journal data in three formats: text/plain: the text format known from /var/log/messages application/json: the journal entries formatted as JSON application/vnd.fdo.journal: the binary export format of the journal The HTTP server also serves a small HTML5 app that makes use of the JSON serialization to present the journal data to the user. Examples: This downloads the journal in text format: # systemctl start systemd-journal-gatewayd.service # wget http://localhost:19531/entries Same for JSON: # curl -H"Accept: application/json" http://localhost:19531/entries Access via web browser: $ firefox http://localhost:19531/