Rewrite Get Started for Logs

[theletterf]

Rewite https://www.elastic.co/docs/solutions/observability/logs/get-started-with-system-logs following the structure in #2310

Also in scope:

• https://www.elastic.co/docs/solutions/observability/logs
• https://www.elastic.co/docs/solutions/observability/logs/stream-any-log-file
• https://www.elastic.co/docs/solutions/observability/logs/stream-any-log-file

Coordinate with @mdbirnstiehl