Support outputting systemd/journalctl logs in JSON format

[6A61736F6E206E61646572]

I would like to have the journalctl logs shown in logDNA to be in JSON format.

Would it be possible to add an env var to enable journald to output logs in JSON format?

Such that when enabled it would change 'export' in the code below to 'json-pretty':

logdna-agent-v2/common/journald/src/journalctl/mod.rs

Lines 253 to 263 in d71e6f1

	pub fn create_journalctl_source() -> Result<impl Stream<Item = LineBuilder>, std::io::Error> {
	let mut journalctl_process = tokio::process::Command::new(JOURNALCTL_CMD)
	// The current boot
	.arg("-b")
	// follow
	.arg("-f")
	// set export format
	.arg("-o")
	.arg("export")
	.stdout(Stdio::piped())
	.spawn()?;

Or otherwise if there is another method that can achieve it at the moment?