Fetch logs of particular steps

[nineinchnick]

There's a log table already, but it fetches logs of all steps in a job. This is often too much to handle in a single page.

Instead, it would be useful to try to fetch logs for particular steps in a job, after identifying failing steps. This is not documented, but the URL is: {owner}/{repo}/commit/{sha}/checks/{jobId}/logs/{stepNumber}. This could map to a table called step_logs and would have to support predicate pushdown for all params in that URL.

[nineinchnick]

Note this will most likely require #40 to be useful, since steps will usually be joined with the jobs table.

[nineinchnick]

There's no API for this. We'd have to split logs based on the block comments.

I guess I'll just try to finish fetching job logs, that is add splitting them into parts to avoid reaching the internal Trino page limit.